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Periodic classification of elements is used to examine the
(a) periodic trends in physical properties of elements
(b) periodic trends in chemical properties of elements
(c) Both (a) and (b)
(d) None of the above
Cl, Br, I, if this is Dobereiner’s triad and the atomic masses of Cl and I are 35.5 and 127 respectively the atomic mass of Br is
(a) 162.5 (b) 91.5
(c) 81.25 (d) 45.625
If the two members of a Dobereiner triad are phosphorus and antimony, the third member of this triad is
(a) arsenic (b) sulphur
(c) iodine (d) calcium
The law of triads is applicable to a group of
(a) Cl, Br, I (b) C, N, O
(c) Na, K, Rb (d) H, O, N
In 1800, only ….X…. elements were known. Here, X refers to
(a) 63 (b) 31
(c) 114 (d) 92
Johann Doberiner gave the idea of trends among physical and …X… of several groups of three elements. Here, X refers to
(a) atomic number (b) atomic mass
(c) chemical properties (d) None of these
Which of the following is the correct set of elements to Dobereiner’s triads ?
On which of the following Dobereiner’s Triad law is not applicable?
(a) Cl, Br, I (b) Ca, Sr, B
(c) F, Cl, Br (d) Li, Na, K
Newlands could classify elements only upto –
(a) copper (b) chlorine
(c) calcium (d) chromium
According to Newlands theory, when elements are arranged in the order of increasing atomic weight which number element had similar properties to the first element.
(a) third (b) seventh
(c) eighth (d) sixth
A mixture of sand and iodine can be separated by
(a) crystallisation (b) distillation
(c) sublimation (d) fractionation
Difference in density is the basis of
(a) ultrafiltration (b) molecular sieving
(c) molecular attraction (d) gravity separation
Which of the following is an example of a heterogeneous substance?
(a) Bottled water (b) Table salt
(c) Pieces of copper (d) Candle
Which of the following substances cannot be separated in to its constituents by physical methods?
(a) Sugar and water solution
(b) Salt and sugar
(c) Solid glucose
(d) Both (a) and (b)
Which of the following pair of substances contain element and compound within a pair ?
(A) O2, CH4 (B) H2, O2
(C) N2, CO2 (D) Na, CO
(a) A, C, D (b) B only
(c) C and D (d) All of these
Which of the following statements about a compound is incorrect?
(a) A molecule of a compound has atoms of different elements.
(b) A compound cannot be separated into its constituent elements by physical methods of separation.
(c) A compound retains the physical properties of its constituent elements.
(d) The ratio of atoms of different elements in a compound is fixed.
Choose the correct combination Element Compound Mixture
(a) Ammonia Sodium Air
(b) Water Sugar Aqueous sugar solution
(c) Hydrogen Oxygen Water
(d) Silver Water Air
Choose the correct statement.
(a) The particle s in liquids are more closely held than gases but less free to move than solids.
(b) The particles of solids are arranged in orderly fashion but they can move as freely as liquids.
(c) The particles of gases are far apart as compared to
solids and liquids and their movement is easy and fast.
(d) The particles of gases moves faster than liquids only when the gases are heated.
A mixture contains two or more substances in____ which are called its _____.
(a) fixed ratio, compounds
(b) fixed ratio, elements
(c) any ratio, components
(d) any ratio, elements
Which one of these is not a pure compound?
(a) O3 (b) H2O2
(c) H2O (d) Sucrose solution
One fermi is
(a) 10-15 cm (b) 10 -13 cm
(c) 10 -10 cm (d) 10 -12 cm
The prefix 1018 is
(a) giga (b) kilo
(c) exa (d) nano
The prefix zepto stands for (in m)
(a) 109 (b) 10-12
(c) 10 -15 (d) 10 -21
The unit J Pa-1 is equivalent to
(a) m3 (b) cm3
(c) dm3 (d) None of these
Which has highest weight ?
(a) 1 m3 of water (b) A normal adult man
(c) 10 litre of Hg (d) All have same weight
Which one of the following set of units represents the smallest and largest amount of energy respectively?
(a) J and erg (b) erg and cal
(c) cal and eV (d) eV and L-atm
A measured temperature on Fahrenheit scale is 200 °F. What will this reading be on Celsius scale ?
(a) 40° C (b) 94° C
(c) 93.3 °C (d) 30° C
Which of the following is not a SI unit?
(a) metre (b) candela
(c) mole (d) litre
The prefix 10-24 is
(a) yotta (b) zeta
(c) yocto (d) zepto
Many countries use Fahrenheit scale for expressing temperature of atmosphere. If temperature in any such country is measured 41°F then what is its value in celcius scale and would you expect hot or cold atmosphere in that country?
(a) 15°C, cold (b) 25°C, normal
(c) 5°C, cold (d) 41°C, hot
A sample was weighted using two different balances. The
(i) 3.929 g (ii) 4.0 g
How would the weight of the sample be reported?
(a) 3.93 g (b) 3g
(c) 3.9 g (d) 3.929 g
Two students performed the same experiment separately and each one of them recorded two readings of mass which are given below. Correct reading of mass is 3.0 g. On the basis of given data, mark the correct option out of the following statements.
A 3.01 2.99
B 3.05 2.95
(a) Results of both the students are neither accurate nor
(b) Results of student A are both precise and accurate.
(c) Results of student B are neither precise nor accurate.
(d) Results of student B are both precise and accurate.
0.00016 can be written as …A… in scientific notaiton. Here, A refers to
(a) 1.6 × 10 -4 (b) 24.50 × 10 -9
(c) 2.450 × 10-8 (d) 24.50 × 10 -7
If the true value for an experimental result is 6.23 and the results reported by three students X, Y and Z are :
X : 6.18 and 6.28
Y : 6.20 and 6.023
Z : 6.22 and 6.24
Which of the following option is correct :
(a) X precise, Y accurate, Z precise and accurate.
(b) X precise and accurate, Y not precise, Z precise
(c) Both X & Z precise & accurate, Y not precise.
(d) Both X & Y neither precise nor accurate, Z both precise and accurate.
In the final answer of the expression
(29.2 – 20.2)(1.79 x 10-5)/1.37
the number of significant figures is :
(a) 1 (b) 2
(c) 3 (d) 4
The number of significant figures for the three numbers 161 cm, 0.161 cm, 0.0161 cm are
(a) 3,4 and 5 respectively (b) 3,4 and 4 respectively
(c) 3,3 and 4 respectively (d) 3,3 and 3 respectively
Given P = 0.0030m, Q = 2.40m, R = 3000m, Significant figures in P, Q and R are respectively
(a) 2, 2, 1 (b) 2, 3, 4
(c) 4, 2, 1 (d) 4, 2, 3
If the density of a solution is 3.12 g mL-1, the mass of 1.5 mL solution in significant figures is______.
(a) 4.7 g (b) 4680 × 10-3 g
(c) 4.680 g (d) 46.80 g
In which of the following number all zeros are significant?
(a) 0.0005 (b) 0.0500
(c) 50.000 (d) 0.0050
The correctly reported answer of addition of 29.4406, 3.2 and 2.25 will have significant figures
(a) 3 (b) 4
(c) 2 (d) 5
The number of significant figures in 10.3106 g is
(a) 2 (b) 3
(c) 1 (d) 6
Choose the correct option that represents the result of the given calculation to the appropriate number of significant figures:
(43.0 * 0.0243)/(0.340 * 4)
(a) 0.768 (b) 0.77
(c) 0.76 (d) 0.7683
Arrange the numbers in increasing no. of significant figures. 0.002600, 2.6000, 2.6, 0.260
(a) 2.6 < 0.260 < 0.002600 < 2.6000
(b) 2.6000 < 2.6 < 0.002600 < 0.260
(c) 0.260 < 2.6 < 0.002600 < 2.6000
(d) 0.002600 < 0.260 < 2.6 < 2.6000
Dimension of pressure are same as that of
(a) Energy (b) Force
(c) Force per unit volume (d) Energy per unit volume
n g of substance X reacts with m g of substance Y to form p g of substance R and q g of substance S. This reaction can be represented as, X + Y = R + S. The relation which can be established in the amounts of the reactants and the products will be
(a) n – m = p – q (b) n + m = p + q
(c) n = m (d) p = q
20 g of CaCO3 on heating gave 8.8 g of CO2 and 11.2 g of CaO. This is in accordance with
(a) The law of conservation of mass.
(b) The law of constant composition.
(c) The law of reciprocal proportion.
(d) None of these
Which of the following is the best example of law of conservation of mass?
(a) 12 g of carbon combines with 32 g of oxygen to form 44 g of CO2
(b) When 12 g of carbon is heated in a vacuum there is no change in mass
(c) A sample of air increases in volume when heated at constant pressure but its mass remains unaltered
(d) The weight of a piece of platinum is the same before and after heating in air
Which of the following statements is correct about the reaction given below ?
4Fe(s) + 3O2 (g) → 2Fe2O3(g)
(a) Total mass of iron and oxygen in reactants = total mass of iron and oxygen in product therefore, it follows law of conservation of mass.
(b) Total mass of reactants = total mass of product; therefore, law of multiple proportions is followed.
(c) Amount of Fe2O3 can be increased by reducing the amount of any one of the reactants (iron or oxygen).
(d) Amount of Fe2O3 produced will decrease if the amount of any one of the reactants (iron or oxygen) is taken in excess.
In an experiment 4.2 g of NaHCO3 is added to a solution of acetic acid weighing 10.0 g, it is observed that 2.2 g of CO2 is released into the atmosphere. The residue left behind is found to weigh 12.0 g
The above observations illustrate
(a) law of definite proportions.
(b) law of conservation of mass
(c) law of multiple proportions
(d) None of these
In one experiment, 4g of H2 combine with 32g of O2 to form 36g of H2O. In another experiment, when 50g of H2 combine with 400g of O2 then 450g of H2O is formed. Above two experiments follow
(a) The law of conservation of mass
(b) The law of constant composition
(c) Both (a) and (b)
(d) Neither (a) nor (b)
Irrespective of the source, pure sample, of water always yields 88.89% mass of oxygen and 11.11% mass of hydrogen. This is explained by the law of
(a) conservation of mass (b) multiple proportions
(c) constant composition (d) constant volume
The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. The illustrate the law of
(a) constant proportions (b) conservation of mass
(c) multiple proportions (d) reciprocal proportions
The law of definite proportions was given by –
(a) John Dalton (b) Humphry Davy
(c) Proust (d) Michael Faraday
Which one of the following pairs of compounds illustrate
the law of multiple proportions ?
(a) H2O and Na2O (b) MgO and Na2O
(c) Na2O and BaO (d) SnCl2 and SnCl4
Among the following pairs of compounds, the one that illustrates the law of multiple proportions is
(a) NH3 and NCl3 (b) H2S and SO2
(c) CS2 and FeSO4 (d) CuO and Cu2O
Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead from one oxide was half the weight of lead obtained from the other oxide. The data illustrates
(a) law of reciprocal proportions
(b) law of constant proportions
(c) law of multiple proportions
(d) law of equivalent proportions
In compound A, 1.00g of nitrogen unites with 0.57g of oxygen. In compound B, 2.00g of nitrogen combines with 2.24g of oxygen. In compound C, 3.00g of nitrogen combines with 5.11g of oxygen. These results obey the following law
(a) law of constant proportion
(b) law of multiple proportion
(c) law of reciprocal proportion
(d) Dalton’s law of partial pressure
Which of the following statements indicates that law of multiple proportion is being followed.
(a) Sample of carbon dioxide taken from any source will always have carbon and oxygen in the ratio 1 : 2.
(b) Carbon forms two oxides namely CO2 and CO, where masses of oxygen which combine with fixed mass of carbon are in the simple ration 2 : 1.
(c) When magnesium burns in oxygen, the amount of magnesium taken for the reaction is equal to the amount of magnesium in magnesium oxide formed.
(d) At constant temperature and pressure 200 mL of hydrogen will combine with 100 mL oxygen to produce 200 mL of water vapour.
The molecular weight of O2 and SO2 are 32 and 64 respectively. At 15°C and 150 mm Hg pressure, one litre of O2 contains ‘N’ molecules. The number of molecules in two litres of SO2 under the same conditions of temperature and pressure will be :
(a) N/2 (b) 1N
(c) 2N (d) 4N
10 dm3 of N2 gas and 10 dm3 of gas X at the same temperature contain the same number of molecules, the gas X is
(a) CO2 (b) CO
(c) H2 (d) NO
One mole of a gas occupies a volume of 22.4 L. This is derived from
(a) Berzelius’ hypothesis (b) Gay-Lussac’s law
(c) Avogadro’s law (d) Dalton’s law
One of the following combination which illustrates the law of reciprocal proportions ?
(a) N2O3, N2O4, N2O5 (b) NaCl, NaBr, NaI
(c) CS2, CO2, SO2 (d) PH3, P2O3, P2O5
Equal volumes of two gases A and B are kept in a container at the same temperature and pressure. Avogadro’s law is invalid if
(a) the gases are reactive
(b) the gases are non-reactive
(c) gas A has more number of molecules than gas B.
(d) None of these
Molecular mass is defined as the
(a) mass of one atom compared with the mass of one molecule
(b) mass of one atom compared with the mass of one atom of hydrogen
(c) mass of one molecule of any substance compared with
the mass of one atom of C-12
(d) None of the above
1 amu is equal to
The modern atomic weight scale is based on
(a) O16 (b) C12
(c) H1 (d) C13
The percentage weight of Zn in white vitriol [ZnSO4.7H2O] is approximately equal to (Zn = 65,S = 32,O = 16 and H = 1)
(a) 33.65 % (b) 32.56 %
(c) 23.65 % (d) 22.65 %
The average atomic mass of neon based on following data is:
Isotope Relative abundance
(a) 0.33 u (b) 20.187 u
(c) 6.729 u (d) 18.058 u
What is the average atomic mass of bromine from the following data : (abundance is in %)
Isotope Mass Abundance
79Br 78.9183361 50.69
81Br 80.916289 49.31
(a) 79.9 (b) 76.6
(c) 75.9 (d) 69.9
What is the mass of an atom of oxygen (in gm)?
(a) 2.656 × 10-23 (b) 1.567 × 10-22
(c) 2.0 × 10-22 (d) 3.5 × 10-23
If the mass of the one atom is found to be 2.324784× 10-23 g, then this atom can be ?
(a) Oxygen (b) Carbon
(c) Fluorine (d) Nitrogen
What is the mass of 1 molecule of CO.
(a) 2.325 × 10-23 (b) 4.65 × 10-23
(c) 3.732 × 10-23 (d) 2.895 × 10-23
Calculate the volume at STP occupied by 240 gm of SO2.
(a) 64 (b) 84
(c) 59 (d) 73
At S.T.P. the density of CCl4 vapours in g/L will be nearest to:
(a) 6.87 (b) 3.42
(c) 10.26 (d) 4.57
The number of gram molecules of oxygen in 6.02 × 1024 CO molecules is
(a) 10 gm molecules (b) 5 gm molecules
(c) 1 gm molecules (d) 0.5 gm molelcules
The number of oxygen atoms in 4.4 g of CO2 is
(a) 1.2 × 1023 (b) 6 × 1022
(c) 6 × 1023 (d) 12 × 1023
Which has maximum number of molecules?
(a) 7 gm N2 (b) 2 gm H2
(c) 16 gm NO2 (d) 16 gm O2
Number of atoms in 558.5 gram Fe (at. wt. of Fe = 55.85
g mol-1) is
(a) twice that in 60 g carbon
(b) 6.023 x 1022
(c) half that in 8 g He
(d) 558.5 x 6.023 x 1023
The number of molecules in 16 g of methane is
(a) 3.0 × 1023 (b) (6.02/16) × 1023
(c) 6.023 × 1023 (d) (16/3) × 1023
Number of g of oxygen in 32.2 g Na2SO4.10 H2O is
(a) 20.8 (b) 2.24
(c) 22.4 (d) 2.08
CHAPTER-2: STRUCTURE OF ATOM
Which of the scientist were able to prove that atom is no longer non-divisible?
(a) Dalton (b) Michael Faraday
(c) Thomson (d) Chadwick
Which of the following is never true for cathode rays ?
(a) They possess kinetic energy.
(b) They are electromagnetic waves.
(c) They produce heat.
(d) They produce mechanical pressure.
Cathode rays are deflected by
(a) an electric field only (b) magnetic field only
(c) by both (d) by none
Which of the following statement is not correct about the characteristics of cathode rays?
(a) They start from the cathode and move towards the anode.
(b) They travel in straight line in the absence of an external electrical or magnetic field.
(c) Characteristics of cathode rays do not depend upon the material of electrodes in cathode ray tube.
(d) Characteristics of cathode rays depend upon the nature of gas present in the cathode ray tube.
Which of the following statements about the electron is incorrect?
(a) It is negatively charged particle
(b) The mass of electron is equal to the mass of neutron.
(c) It is a basic constituent of all atoms.
(d) It is a constituent of cathode rays.
While performing cathode ray experiments, it was observed that there was no passage of electric current under normal conditions. Which of the following can account for this observation ?
(a) Dust particles are present in air
(b) Carbon dioxide is present in air
(c) Air is a poor conductor of electricity under normal conditions
(d) None of the above
Which is not true with respect to cathode rays?
(a) A stream of electrons
(b) Charged particles
(c) Move with speed same as that of light
(d) Can be deflected by magnetic fields
What is the optimum conditions required to study the conduction of electricity through gases.
(a) High pressure and low voltage
(b) High pressure and high voltage
(c) Low pressure and high voltage
(d) Low pressure and low voltage
In discharge tube experiment stream of negatively charged particles travel from
(a) anode to cathode (b) cathode to anode
(c) Both (a) and (b) (d) Electrons does not travel
Millikan performed an experiment method to determine which of the following ?
(a) Mass of the electron (b) Charge of the electron
(c) e/m ratio of electron (d) Both (a) and (b)
The discovery of neutron became very late because :
(a) neutrons are present in nucleus
(b) neutrons are chargeless
(c) neutrons are fundamental particles
(d) all of the above
Which is correct statement about proton ?
(a) Proton is nucleus of deuterium
(b) Proton is α-particle
(c) Proton is ionized hydrogen molecule
(d) Proton is ionized hydrogen atom
The lightest particle is :
(a) α -particle (b) positron
(c) proton (d) neutron
When beryllium is bombarded with alpha particles (Chadwick’s experiment) extremely penetrating radiations, which cannot be deflected by electrical or magnetic field are
given out. These are :
(a) A beam of protons
(b) Alpha rays
(c) A beam of neutrons
(d) A beam of neutrons and protons
Neutron is discovered by
(a) Chadwick (b) Rutherford
(c) Yukawa (d) Dalton
Suppose beam containing all three fundamental subatomic particles are allowed to pass through an electric field as shown in figure. The subatomic particles detected at three points A, B and C on the screen respectively are ?
(a) Protons, neutrons, electrons
(b) Electrons, neutrons, protons
(c) Electrons, protons, neutrons
(d) Neutrons, protons, electrons
Which of the following properties of atom could be explained
correctly by Thomson Model of atom?
(a) Overall neutrality of atom.
(b) Spectra of hydrogen atom.
(c) Position of electrons, protons and neutrons in atom.
(d) Stability of atom.
Arrange the following in terms of penetrating power.
α-rays, β -rays, γ -rays
(a) α > β > γ (b) α < β < γ (c) α > β < γ (b) α > γ > β
Which of the rays are not deflected by the electric and
magnetic field ?
(a) γ -rays (b) X-rays
(c) β -rays (d) Both (a) and (b)
Rutherford’s experiment on the scattering of α -particles
showed for the first time that the atom has :
(a) electrons (b) protons
(c) nucleus (d) neutrons
When atoms are bombarded with alpha particles, only, a few in million suffer deflection, others pass out undeflected.
This is because
(a) the force of repulsion on the moving alpha particle is small
(b) the force of attraction between alpha particle and oppositely charged electrons is very small
(c) there is only one nucleus and large number of electrons
(d) the nucleus occupies much smaller volume compared to the volume of the atom
Rutherford’s α -particle dispersion experiment concludes
(a) all positive ions are deposited at small part
(b) all negative ions are deposited at small part
(c) proton moves around the electron
(d) neutrons are charged particles
Rutherford’s experiment which established the nuclear model of the atom used a beam of
(a) β -particles which impinged on a metal foil and got absorbed
(b) γ -rays which impinged on a metal foil and ejected electrons
(c) helium atoms, which impinged on a metal foil and got scattered
(d) helium nuclei, which impinged on a metal foil and got scattered
Which of the following scientists explained his model on the basis of centrifugal force ?
(a) Thomson (b) Dalton
(c) Millikan (d) Rutherford
The number of neutrons in dipositive zinc ion with mass number 70 is
(a) 34 (b) 36
(c) 38 (d) 40
The number of electrons in [4019K]-1 is
(a) 20 (b) 40
(c) 18 (d) 19
Which of the following does not contain number of neutrons equal to that of 4018Ar ?
Number of protons, neutrons and electrons in the element
(a) 89, 89, 242 (b) 89, 142, 89
(c) 89, 71, 89 (d) 89, 231, 89
An element has atomic number 11 and mass number 24. What does the nucleus contain?
(a) 11 protons, 13 neutrons
(b) 11 protons, 13 neutrons, 13 electrons
(c) 13 protons, 11 neutrons
(d) 13 protons, 11 electrons
The number of electrons and neutrons of an element is 18 and 20 respectively. Its mass number is
(a) 2 (b) 17
(c) 37 (d) 38
‘A’ represents mass no. and Z represents atomic no. then
α – decay is characterized by
(a) Z increases by 2, A decreases by 4
(b) Z decreases by 2, A increases by 4
(c) Z decreases by 2, A decreases by 4
(d) Z increases by 2, A increases by 4.
(a) only neutrons
(b) neutrons + protons
(c) neutrons + protons + electrons
(d) neutrons + electrons
Atoms with same mass number but different atomic numbers
(a) isotopes (b) isobars
(c) isochores (d) None of these
Which of the following
What is the difference between two species if one has atomic mass = 14 and atomic number = 7 whereas the other has atomic mass = 14 and atomic number = 6 ?
(a) Neutrons (b) Protons
(c) Electrons (d) All of these
From the data given below A, B, C and D respectively are,
(A) 10 e– , atomic no. 11 (B) 10 e–, atomic no. 6
(C) 10 e– , atomic no. 10 (D) 10 e– , atomic no. 9
(a) Na+ , C4- , Ne, F – (b) C4- , Ne, Na– , F–
(c) F– , Na+ , Ne, C4- (d) F+ , Na+, C4- , Ne
If the wavelength of the electromagnetic radiation is increased to thrice the digital value, then what will be the percent change in the value of frequency of the electromagnetic radiation.
(a) Increases by 33% (b) Decreases by 33%
(c) Increases by 66% (d) Decreases by 66%
Which is the correct schematic representation of the graph of black body radiation.
The ideal body, which emits and absorbs radiations of all frequencies, is called a black body and the radiation emitted by such a body is called
(a) white body radiation (b) black body radiation
(c) black body emission (d) None of these
Which one of the following is not the characteristic of Planck’s quantum theory of radiation ?
(a) The energy is not absorbed or emitted in whole number
or multiple of quantum
(b) Radiation is associated with energy
(c) Radiation energy is not emitted or absorbed continuously but in the form of small packets called quanta
(d) This magnitude of energy associated with a quantum is proportional to the frequency
Which of the following is related with both wave nature and particle nature ?
(a) Interference (b) E = mc2
(c) Diffraction (d) E = hυ
The value of Planck’s constant is 6.63 × 10-34 Js. The velocity of light is 3.0 × 108 m s-1. Which value is closest to the wavelength in nanometers of a quantum of light with
frequency of 8 × 1015 s-1 ?
(a) 3 × 10 7 (b) 2 × 10-25
(c) 5 × 10 -18 (d) 4 × 10
In the photo-electron emission, the energy of the emitted electron is
(a) greater than the incident photon
(b) same as than of the incident photon
(c) smaller than the incident photon
(d) proportional to the intensity of incident photon
When a metal surface is exposed to solar radiations
(a) The emitted electrons have energy less than a maximum value of energy depending upon frequency of incident radiations
(b) The emitted electrons have energy less than maximum value of energy depending upon intensity of incident radiation
(c) The emitted electrons have zero energy
(d) The emitted electrons have energy equal to energy of photons of incident light
In photoelectric effect, at which frequency electron will be ejected with certain kinetic energy (0 = threshold
(a) υ > υo (b) υo > υ
(c) υo ≥ υ (d) υ ≥ υo
In continous spectrum light of (i)___ wavelength is deviated the ii___
(a) (i) = longest, least (b) (ii) = shortest, least
(c) (i) = shortest, most (d) (i) = longest, most
Which of the following statements do not form a part of Bohr’s model of hydrogen atom ?
(a) Energy of the electrons in the orbits are quantized
(b) The electron(s) in the orbit nearest to the nucleus has the lowest energy
(c) Electrons revolve in different orbits around the nucleus
(d) The position and velocity of the electrons in the orbit cannot be determined simultaneously
An electron from one Bohr stationary orbit can go to next higher orbit
(a) by emission of electromagnetic radiation
(b) by absorption of any electromagnetic radiation
(c) by absorption of electromagnetic radiation of particular frequency
(d) without emission or absorption of electromagnetic radiation
For a Bohr atom angular momentum M of the electron is (n = 0, 1, 2, …..) :
According to Bohr’s theory, the angular momentum of an electron in 5th orbit is
(a) 10 h / π (b) 2.5 h / π
(c) 25 h / π (d) 1.0 h / π
In Bohr’s model, atomic radius of the first orbit is y, the radius of the 3rd orbit, is
(a) y / 3 (b) y
(c) 3y (d) 9y
The radius of 1st Bohr’s orbit for hydrogen atom is ‘r’. The radius of second Bohr’s orbit is
(a) 4r (b) r3
(c) 4r2 (d) r1/3
The third line of the Balmer series, in the emission spectrum
of the hydrogen atom, is due to the transition from the
(a) fourth Bohr orbit to the first Bohr orbit
(b) fifth Bohr orbit to the second Bohr orbit
(c) sixth Bohr orbit to the third Bohr orbit
(d) seventh Bohr orbit to the third Bohr orbit
Which one of the following pairs is not correctly matched ?
(b) J.J. Thomson-Electron
(c) J.H. Chadwick-Neutron
If r is the radius of the first orbit, the radius of nth orbit of H-atom is given by
(a) rn2 (b) rn
(c) r/n (d) r2 n2
The radius of hydrogen atom in the ground state is 0.53 Å. The radius of Li2+ ion (atomic number = 3) in a similar state is
(a) 0.17 Å (b) 0.265 Å
(c) 0.53 Å (d) 1.06 Å
The energy of an electron in the nth Bohr orbit of hydrogen atom is
The energy of second Bohr orbit of the hydrogen atom is -328 kJ mol-1; hence the energy of fourth Bohr orbit would be:
(a) -41 kJ mol-1 (b) -82 kJ mol-1
(c) -164 kJ mol-1 (d) -1312 kJ mol-1
In a hydrogen atom, if energy of an electron in ground state is 13.6. eV, then that in the 2nd excited state is
(a) 1.51 eV (b) 3.4 eV
(c) 6.04 eV (d) 13.6 eV.
The energy of an electron in second Bohr orbit of hydrogen atom is :
(a) –5.44 × 10-19 eV (b) –5.44 × 10-19 cal
(c) –5.44 × 10-19 kJ (d) –5.44 × 10-19 J
The energy of electron in first energy level is – 21.79 x10-12 erg per atom. The energy of electron in second energy level is :
(a) -54.47×10-12 erg atom-1
(b) – 5.447 x 10 -12 erg atom -1
(c) – 0.5447 x 10 -12 erg atom -1
(d) – 0.05447 x 10 -12 erg atom -1
The ionisation potential of a hydrogen atom is –13.6 eV. What will be the energy of the atom corresponding to n = 2.
(a) – 3.4 eV (b) – 6.8 eV
(c) – 1.7 eV (d) –2.7 eV
The line spectrum of He+ ion will resemble that of
(a) hydrogen atom (b) Li+ ion
(c) helium atom (d) lithium atom
What does negative sign in the electronic energy for hydrogen atom convey.
(a) Energy of electron when n = ∞
(b) The energy of electron in the atom is lower than the energy of a free electron in motion
(c) The energy of electron in the atom is lower than the energy of a free electron of rest
(d) The energy of electron decreases as it moves away from nucleus
In which of the following Bohr’s stationary state, the electron will be at maximum distance from the nucleus ?
(a) IInd (b) Ist
(c) Vth (d) IIIrd
The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097×107 m-1)
(a) 406 nm (b) 192 nm
(c) 91 nm (d) 9.1×10–8 nm
The frequency of radiation emitted when the electron falls from n = 4 to n =1 in a hydrogen atom will be (Given : ionization energy of H=2.18 ×10-18J atom–1and h = 6.625 ×10-34 J s )
(a) 1.54×1015 s -1 (b) 1.03×10 15 s-1
(c) 3.08×1015 s -1 (d) 2.00×1015 s -1
Which of the following transitions of electrons in the hydrogen atom will emit maximum energy ?
(a) n5 → n4 (b) n4 → n3
(c) n3 → n2 (d) all will emit same energy
The first emission line of hydrogen atomic spectrum in the Balmer series appears is (R = Rydberg constant)
(a) (5/56)R cm-1 (b) (3/4)R cm-1 (c) (7/144)R cm-1 (d) (9/400)R cm-1
According to the Bohr theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon ?
(a) n = 6 to n = 1 (b) n = 5 to n = 4
(c) n = 6 to n = 5 (d) n = 5 to n = 3
The wavelength (in cm) of second line in the Lyman series of hydrogen atomic spectrum is (Rydberg constant= R cm-1)
(a) 8R/9 (b) 9/(8R) (c) 4/(3R) (d) 3R/4
The shortest wavelength in hydrogen spectrum of Lyman series when RH = 109678 cm-1 is
(a) 1002.7Å (b) 1215.67Å
(c) 1127.30Å (d) 911.7Å
What is the expression of frequency ( υ ) associated with absorption spectra of the photon.
Bohr model can explain :
(a) the solar spectrum
(b) the spectrum of hydrogen molecule
(c) spectrum of any atom or ion containing one electron only
(d) the spectrum of hydrogen atom only
Which of the following statements do not form a part of Bohr’s model of hydrogen atom ?
(a) Energy of the electrons in the orbits are quantized
(b) The electron in the orbit nearest the nucleus has the lowest energy
(c) Electrons revolve in different orbits around the nucleus
(d) The position and velocity of the electrons in the orbit cannot be determined simultaneously.
Bohr’s theory can be applied to which of the following ions.
(a) Na+ (b) Be2+
(c) Li+ (d) Li2+
Bohr’s model is not able to account for which of the following.
(a) Stability of atom.
(b) Spectrum of neutral helium atom.
(c) Energy of free electron at rest.
(d) Calculation of radii of the stationary states
If electron, hydrogen, helium and neon nuclei are all moving with the velocity of light, then the wavelength associated with these particles are in the order
(a) Electron > hydrogen > helium > neon
(b) Electron > helium > hydrogen > neon
(c) Electron < hydrogen < helium < neon
(d) Neon < hydrogen < helium < electron
The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 metres per second is approximately
(a) 10-31 metres (b) 10-16 metres
(c) 10-25 metres (d) 10-33 metres
Planck’s constant, h = 6.63 × 10-34 Js
If the energy difference between the ground state of an atom and its excited state is 4.4 × 10-4 J, the wavelength of photon required to produce the transition :
(a) 2.26 × 10-12 m (b) 1.13 × 10-12 m
(c) 4.52 × 10-12 m (d) 4.52 × 10-12 m
If the Planck’s constant h = 6.6× 10-34 Js, the de Broglie wavelength of a particle having momentum of 3.3 × 10-24
kg ms –1 will be
(a) 0.002 Å (b) 0.5Å
(c) 2Å (d) 500Å
If the Planck’s constant h = 6.6× 10-34 Js, the de Broglie wavelength of a particle having momentum of 3.3 × 10-24 kg ms-1 will be
(a) 0.002 Å (b) 0.5Å
(c) 2Å (d) 500Å
The mass of a photon with a wavelength equal to 1.54 × 10-8 cm is
(a) 0.8268 × 10-34 kg (b) 1.2876 × 10-33 kg
(c) 1.4285 × 10-32 kg (d) 1.8884 × 10-32 kg
The values of Planck’s constant is 6.63 × 10-34 Js. The velocity of light is 3.0 × 108 m s-1 . Which value is closest to the wavelength in nanometres of a quantum of light with frequency of 8 × 1015 s-1?
(a) 5 × 10-18 (b) 4 × 10
(c) 3 × 107 (d) 2 × 1025
The de Broglie wavelength of a car of mass 1000 kg and velocity 36 km/hr is:
(a) 6.626 × 10-34 m (b) 6.626 × 10-38 m
(c) 6.626 × 10-31 m (d) 6.626 × 10-30 m
Heisenberg uncertainty principle can be explained as
Heisenberg’s uncertainity principle is applicable to
(a) atoms only (b) electron only
(c) nucleus only (d) any moving object
The position of both, an electron and a helium atom is known within 1.0nm. Further the momentum of the electron is known within 5.0 × 10-26 kg ms-1 . The minimum uncertainty in the measurement of the momentum of the helium atom is
(a) 50 kg ms-1 (b) 80 kg ms-1
(c) 8.0 × 10–26 kg ms-1 (d) 5.0 × 10–26 kg ms-1
Uncertainty in the position of an electron (mass = 9.1 × 10-31 kg) moving with a velocity 300 m s-1 , accurate upto 0.001% will be (h = 6.63 × 10-34 Js)
(a) 1.92 × 10-2 m (b) 3.84 × 10-2 m
(c) 19.2 × 10-2 m (d) 5.76 × 10-2 m
The uncertainty in the position of an electron (mass =9.1 × 10-28 g) moving with a velocity of 3.0 × 104 cm s-1 accurate upto 0.011% will be
(a) 1.92 cm (b) 7.68 cm
(c) 0.175 cm (d) 3.84 cm.
The Heisenberg uncertainity principle will be most significant for which of the following object ?
(a) Object A of mass 9.11 × 10-30 kg
(b) Object B of mass 9.11 × 10-28 g
(c) Object C of mass 9.11 × 10-24 mg
(d) Object D of mass 9.11 × 10-28 kg
The orientation of an atomic orbital is governed by
(a) Spin quantum number
(b) Magnetic quantum number
(c) Principal quantum number
(d) Azimuthal quantum number
For which one of the following sets of four quantum numbers, an electron will have the heighest energy?
n l m s
(a) 3 2 1 1/2
(b) 4 2 –1 1/2
(c) 4 1 0 –1/2
(d) 5 0 0 –1/2
Which of the following sets of quantum numbers is correct for an electron in 4f orbital ?
(a) n = 4, l = 3, m = + 1, s = + ½
(b) n = 4, l = 4, m = – 4, s = – ½
(c) n = 4, l = 3, m = + 4, s = + ½
(d) n = 3, l = 2, m = – 2, s = + ½
What is the correct orbital designation of an electron with the quantum number, n = 4, l = 3, m = – 2, s = 1/2 ?
(a) 3s (b) 4 f
(c) 5p (d) 6s
Which of the following represents correct set of the four quantum numbers for an electron in a 4d subshell ?
(a) 4, 2, 1, 0 (b) 4, 2, 1, – 1/2
(c) 4, 3, 2, + 1/2 (d) 4, 3, – 2, – 1/2
The total number of electrons that can be accommodated in all orbitals having principal quantum number 2 and azimuthal quantum number 1 is
(a) 2 (b) 4
(c) 6 (d) 8
For azimuthal quantum number l = 3, the maximum number of electrons will be
(a) 2 (b) 6
(c) 0 (d) 14
Which of the following is not permissible arrangement of electrons in an atom?
(a) n = 5, l = 3, m = 0, s = + 1/2
(b) n = 3, l = 2, m = – 3, s = – 1/2
(c) n = 3, l = 2, m = – 2, s = – 1/2
(d) n = 4, l = 0, m = 0, s = – 1/2
Which of the following sets of quantum numbers represents the highest energy of an atom?
(a) n = 3, l = 0, m = 0, s = +1/2
(b) n = 3, l = 1, m = 1, s = +1/2
(c) n = 3, l = 2, m = 1, s = +1/2
(d) n = 4, l = 0, m = 0, s = +1/2
Which set of quantum numbers are not possible?
n l m s
(a) 3 2 0 +1/2
(b) 2 2 1 +1/2
(c) 1 0 0 –1/2
(d) 3 2 –2 +1/2
What will be the sum of all possible values of l and m for n = 5 ?
(a) 12 (b) 13
(c) 4 (d) 9
The following quantum numbers are possible for how many orbital(s) n = 3, l = 2, m = +2 ?
(a) 1 (b) 3
(c) 2 (d) 4
The orbitals are called degenerate when
(a) they have the same wave functions
(b) they have the same wave functions but different energies
(c) they have different wave functions but same energy
(d) they have the same energy
The number of spherical nodes in 3p orbitals are
(a) one (b) three
(c) two (d) None of these
Which of the following graph correspond to one node
If there are five radial nodes, then what can be the correct representation of the orbital for n = 8.
(a) 8d (b) 8s
(c) 8p (d) 8f
What can be the representation of the orbital having 3 angular nodes and n = 5.
(a) 5d (b) 5f
(c) 5p (d) 5s
The number of orbitals present in the fifth shell will be
(a) 25 (b) 10
(c) 50 (d) 20
Arrange the orbital of same shell in the increasing order of shielding strength of the outer shell of electrons. s, f, d, p
(a) s < p < d < f (b) s > p < d < f (c) s > p > d < f (d) s > p > d > f
Which of the following is not correct for electronic distribution in the ground state ?
The electronic configuration of gadolinium (Atomic number 64) is
(a) [Xe] 4f 8 5d0 6s2 (b) [Xe] 4f3 5d5 6s2
(c) [Xe] 4f 6 5d26s2 (d) [Xe] 4f7 5d1 6s2
The order of filling of electrons in the orbitals of an atom will be
(a) 3d, 4s, 4p, 4d, 5s (b) 4s, 3d, 4p, 5s, 4d
(c) 5s, 4p, 3d, 4d, 5s (d) 3d, 4p, 4s, 4d, 5s
The number of d-electrons retained in Fe2+ (At. no. of Fe = 26) ion is
(a) 4 (b) 5
(c) 6 (d) 3
The electronic configuration of an element is 1s2, 2s2 2p6, 3s2 3p6 3d5, 4s1. This represents its
(a) excited state (b) ground state
(c) cationic form (d) anionic form
Number of unpaired electrons in N2+ is
(a) 2 (b) 0
(c) 1 (d) 3
An ion has 18 electrons in the outermost shell, it is
(a) Cu+ (b) Th4+
(c) Cs+ (d) K+
In a given atom no two electrons can have the same values for all the four quantum numbers. This is called
(a) Hund’s Rule (b) Aufbau principle
(c) Uncertainty principle (d) Pauli’s exclusion principle
The electronic configuration of Cu (atomic number 29) is
(a) 1s2 , 2s2 2 p6 ,3s23p6 , 4s23d9
(b) 1s2 ,2s22 p6,3s23 p6 3d10,4s1
(c) 1s2,2s22p6,3p23p6 ,4s24p6,5s25p1
(d) 1s2 ,2s2 2 p6,3p23p6 ,4s24 p6 3d3
The orbital diagram in which the Aufbau principle is violated is :
If n = 6, the correct sequence for filling of electrons will be :
(a) ns → (n – 2) f → (n – 1) d → np
(b) ns → (n – 1) d → (n – 2) f → np
(c) ns → (n – 2) f → np → (n – 1) d
(d) ns → np (n – 1) d → (n – 2) f
Maximum number of electrons in a subshell of an atom is determined by the following:
(a) 2 l + 1 (b) 4 l – 2
(c) 2 n2 (d) 4 l + 2
The correct order of increasing energy of atomic orbitals is
(a) 5 p < 4 f < 6 s < 5 d (b) 5 p < 6 s < 4 f < 5 d
(c) 5 p < 5 d < 4 f < 6 s (d) None of these
For which element, the valence electron will be present in the highest energy orbital.
(a) 3Li (b) 16S
(c) 20Ca (d) 21Sc
Which of the following electronic configuration of d-orbital
will have highest affinity for gaining an electron?
On the basis of figure given below which of the following statement(s) is/are correct ?
(i) At point B, when only electric field is applied.
(ii) At point C, when both electric and magnetic field is applied.
(iii) At point B, when both electric and magnetic fields are
(iv) At point C, when only magnetic field is applied.
Which of the following is/are correct?
(a) (i) and (ii) (b) only (iii)
(c) (iii) and (iv) (d) (i) and (iii)
Which of the following statements are not correct about electromagnetic radiation ?
(i) Electromagnetic waves require medium to travel.
(ii) Different electromagnetic radiations travel at same speed in vaccum.
(iii) The oscillating electric and magnetic fields produced by oscillating charged particles are perpendicular to each other, but not to the direction of propagation.
(iv) The oscillating electric field and magnetic field are perpendicular to each other, and also to the direction of propagation.
(a) (i), (ii) and (iii) (b) (ii) and (iii)
(c) (i) and (iii) (d) (i) and (iv)
Which of the following statement(s) is/are incorrect regarding photoelectric effect?
(i) The number of electrons ejected is proportional to the intensity of light.
(ii) There is some time lag between the striking of light beam on the metal surface and the ejection of electrons.
(iii) The kinetic energy of ejected electrons depends upon the brightness of light.
(iv) The kinetic energy of the ejected electron is proportional to the frequency of the incident radiation.
(a) (i) and (ii) (b) (ii) and (iii)
(c) (ii) only (d) (ii) and (iv)
For Balmer series in the spectrum of atomic hydrogen, the wave number of each line is given by
where RH is a constant and n1 and n2 are integers. Which of the following statement(s) is (are) correct?
(i) As wavelength decreases, the lines in the series converge.
(ii) The integer n1 is equal to 2.
(iii) The ionization energy of hydrogen can be calculated from the wave number of these lines.
(iv) The line of longest wavelength corresponds to n2 = 3.
(a) (i), (ii) and (iii) (b) (ii), (iii) and (iv)
(c) (i), (i) and (iv) (d) (ii) and (iv)
Which of the following statements of quantum mechanics was in agreement with Bohr’s model?
(i) The path of an electron in an atom can never be determined accurately.
(ii) The energy of electrons in atom is quantized i.e., can only have specific values.
(iii) An orbital cannot contain more than two electrons.
(a) Only (i) (b) (i) and (ii)
(c) Only (ii) (d) (ii) and (iii)
Which of the following statements concerning the quantum numbers are correct ?
(i) Angular quantum number determines the threedimensional shape of the orbital.
(ii) The principal quantum number determines the orientation and energy of the orbital.
(iii) Magnetic quantum number determines the size of the orbital.
(iv) Spin quantum number of an electron determines the orientation of the spin of electron relative to the chosen axis.
The correct set of option is
(a) (i) and (ii) (b) (i) and (iv)
(c) (iii) and (iv) (d) (ii), (iii) and (iv)
Match the columns.
Match the columns.
Match the columns.
Match the columns.
Match the columns.
Match the columns
(a) A – (p), B – (s), C – (r), D – (q)
(b) A – (s), B – (p), C – (r), D – (q)
(c) A – (s), B – (p), C – (q), D – (r)
(d) A – (s), B – (r), C – (p), D – (q)
Match the columns
(a) A – (r), B – (p), C – (t), D – (s)
(b) A – (r), B – (t), C – (s), D – (p)
(c) A – (r), B – (t), C – (p), D – (s)
(d) A – (t), B – (r), C – (p), D – (s)
Match the columns.
Directions : Each of these questions contain two statements, Assertion and Reason. Each of these questions also has four alternative choices, only one of which is the correct answer. You have to select one of the codes (a), (b), (c) and (d) given below.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.
Assertion : The position of an electron can be determined exactly with the help of an electron microscope.
Reason : The product of uncertainty in the measurement of its momentum and the uncertainty in the measurement of the position cannot be less than a finite limit.
Assertion : The radius of the first orbit of hydrogen atom is 0.529Å.
Reason : Radius of each circular orbit (rn) – 0.529Å (n2/Z), where n = 1, 2, 3 and Z = atomic number.
Assertion : All isotopes of a given element show the same type of chemical behaviour.
Reason : The chemical properties of an atom are controlled by the number of electrons in the atom
Assertion : Black body is an ideal body that emits and absorbs radiations of all frequencies.
Reason : The frequency of radiation emitted by a body goes from a lower frequency to higher frequency with an increase in temperature.
Assertion : It is impossible to determine the exact position and exact momentum of an electron simultaneously.
Reason : The path of an electron in an atom is clearly defined.
What is the ratio of mass of an electron to the mass of a proton?
(a) 1 : 2 (b) 1 : 1
(c) 1 : 1837 (d) 1 : 3
The increasing order for the values of e/m (charge/mass) is
(a) e, p, n, α (b) n, p, e, α
(c) n, p, α , e (d) n, α , p, e
In which of the following the amount of deviation from their path in the presence of electric and magnetic field will be maximum?
(a) N2- (b) N3-
(c) N– (d) N
The deflection of the particles from their path in presence of electric and magnetic field will be maximum in which of the following.
(a) O (b) N
(c) U (d) He
Which of the following pairs have identical values of e/m?
(a) A proton and a neutron
(b) A proton and deuterium
(c) Deuterium and an α-particle
(d) An electron and γ-rays
If the alpha-particles are projected against the following atoms Fe, Be, Mg, Al then increasing order in which the alpha-particle feel repulsion will be
(a) Be, Mg, Al, Fe (b) Be, Al, Mg, Fe
(c) Mg, Al, Mg, Fe (d) Al, Mg, Fe, Be
The number of electrons, neutrons and protons in a species are equal to 10, 8 and 8 respectively. The proper symbol of the species is
(a) 16O8 (b) 18 O8
(c) 18Ne10 (d) 16O82-
What will be the difference between electromagnetic radiation shown in A and B respectively ?
(i) Velocity (ii) Wavelength
(iii) Frequency (iv) Energy
(a) (ii) only (b) (ii) and (iv)
(c) (ii), (iii) and (iv) (d) (iv) only
Arrange the electromagnetic radiations a, b, c, d and e in increasing order of energy. Frequencies of a, b and c are 1015, 1014 and 1017 respectively whereas wavelength of
(d) and (e) are 350 nm and 100 nm respectively ?
(a) a, b, c, d, e (b) a, b, d, e, c
(c) a, d, b, e, c (d) b, d, a, e, c
An electron, e1 is moving in the fifth stationary state, and another electron e2 is moving in the fourth stationary state. The radius of orbit of electron, e1 is five times the radius of orbit of electron, e2 calculate the ratio of velocity of electron e1 (v1) to the velocity of electron e2 (v2 ).
(a) 5 : 1 (b) 4 : 1
(c) 1 : 5 (d) 1 : 4
The Li2+ ion is moving in the third stationary state, and its linear momentum is 7.3 × 10-34 kg ms-1. Calculate its angular momentum.
(a) 1.158 × 10-45 kg m2s-1
(b) 11.58 × 10-48 kg m2s-1
(c) 11.58 × 10-48 kg m2s-1
(d) 12 × 10-48 kg m2s-1
The Bohr orbit radius for the hydrogen atom (n = 1) is approximately 0.530 Å. The radius for the first excited state (n = 2) orbit is (in Å)
(a) 0.13 (b) 1.06
(c) 4.77 (d) 2.12
According to Bohr’s theory the energy required for an electron in the Li2+ ion to be emitted from n = 2 state is (given that the ground state ionization energy of hydrogen atom is 13.6 eV)
(a) 61.2 eV (b) 13.6 eV
(c) 30.6 eV (d) 10.2 eV
Among species H, Li2+, He+, Be3+ and Al3+ Bohr’s model was able to explain the spectra of
(a) All of these
(b) None of these
(c) all other species except Be3+
(d) all other species except Al3+
Which of the following levels of H and He+ have same energy respectively ?
(A) 1, 2 (B) 3, 4
(C) 2, 4 (D) 3, 6
(a) A and D (b) A and B
(c) C and D (d) A, C and D
Bohr radius of nth orbit of an atom is given by the expression:
The ratio between kinetic energy and the total energy of the electrons of hydrogen atom according to Bohr’s model is
(a) 2 : 1 (b) 1 : 1
(c) 1 : – 1 (d) 1 : 2
The potential energy of electron present in ground state of Li2+ ion is represented by :
In hydrogen atomic spectrum, a series limit is found at 12186.3 cm-1. Then it belong to
(a) Lyman series (b) Balmer series
(c) Paschen series (d) Brackett series
Which transition in the hydrogen atomic spectrum will have the same wavelength as the transition, n = 4 to n = 2 of He2+ spectrum?
(a) n = 4 to n = 3 (b) n = 3 to n = 2
(c) n = 4 to n = 2 (d) n = 2 to n = 1
Arrange the following elements in the order of ease of detection of wave properties, in the de Broglie experiment. H, Li, Be, B, K
(a) H < Be, B < Li < K. (b) H > Li > K > Be > B
(c) H > Li > Be > B > K (d) H < Li < Be < B < K
A 600 W mercury lamp emits monochromatic rediation of wavelength 331.3 nm. How many photons are emitted from the lamp per second ? (h = 6.626 × 10-34 Js; velocity of light= 3 × 108 ms-1)
(a) 1 × 1019 (b) 1 × 1020
(c) 1 × 1021 (d) 1 × 1023
Calculate the velocity of ejected electron from the metal surface when light of frequency 2 ×1015 Hz fall on the metal surface and the threshold frequency is 7 × 1014 Hz for metal ?
(a) 1.37 × 106 (b) 1.26 × 106
(c) 1.45 × 107 (d) 1.37 × 107
What is the wavelength (in m) of the electron emitted in the above question ?
(a) 5.308 × 10-10 (b) 5.89 × 10-11
(c) 4.37 × 10-13 (d) 3.98 × 10-10
The velocity of particle A is 0.1 ms-1 and that of particle B is 0.05 ms-1. If the mass of particle B is five times that of particle A, then the ratio of de-Broglie wavelengths associated with the particles A and B is
(a) 2 : 5 (b) 3 : 4
(c) 6 : 4 (d) 5 : 2
Two fast moving particles X and Y are associated with de Broglie wavelengths 1 nm and 4 nm respectively. If mass of X in nine times the mass of Y, the ratio of kinetic energies of X and Y would be
(a) 3 : 1 (b) 9 : 1
(c) 5 : 12 (d) 16 : 9
Uncertainty in position of a n electron (mass = 9.1 × 10–28 g) moving with a velocity of 3 × 104 cm/s accurate upto 0.001% will be (use h/4 π ) in uncertainty expression where h = 6.626 ×10-27 erg-second).
(a) 1.93 cm (b) 3.84 cm
(c) 5.76 cm (d) 7.68 cm
The measurement of the electron position is associated with an uncertainty in momentum, which is equal to 1× 10-18 g cm s-1 . The uncertainty in electron velocity is,
(mass of an electron is 9 × 10-28 g)
(a) 1 × 109 cm s-1 (b) 1 × 106 cm s-1
(c) 1 × 105 cm s-1 (d) 1 × 1011 cm s-1
In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity with which the position of the electron can be located is ( h = 6.6 × 10–34 kg m2 s-1 , mass of electron, em = 9.1 × 10–31 kg)
(a) 5.10 × 10-3 m (b) 1.92 × 10-3 m
(c) 3.84 × 10-3 m (d) 1.52 × 10-4 m
If uncertainty in position and momentum are equal, then uncertainty in velocity is :
Which of the following sets of quantum numbers is correct?
(a) n = 5, l = 4, m = 0, s = + ½
(b) n = 3, l = 3, m = +3, s = + ½
(c) n = 6, l = 0, m = +1, s = – ½
(d) n = 4, l = 2, m = +2, s = 0
Which combinations of quantum numbers, n, l , m and s for the electron in an atom does not provide a permissible solution of the wave equation ?
(a) 3, 2, 1, 1/2 (b) 3, 1, 1, -1/2 (c) 3, 3, 1, -1/2 (d) 3, 2, -2, 1/2
An electron has principal quantum number 3. The number of its (i) subshells and (ii) orbitals would be respectively
(a) 3 and 5 (b) 3 and 7
(c) 3 and 9 (d) 2 and 5
The electrons identified by quantum numbers n and :
(A) n = 4, l = 1 (B) n = 4, l = 0
(C) n = 3, l = 2 (D) n = 3, l = 1
can be placed in order of increasing energy as :
(a) (C) < (D) < (B) < (A) (b) (D) < (B) < (C) < (A)
(c) (B) < (D) < (A) < (C) (d) (A) < (C) < (B) < (D)
The five d-orbitals are designated as dxy , dyz , dxz , dx2-y2
and dz2 . Choose the correct statement.
(a) The shapes of the first three orbitals are similar but
that of the fourth and fifth orbitals are different
(b) The shapes of all five d-orbitals are similar
(c) The shapes of the first four orbitals are similar but that
of the fifth orbital is different
(d) Ths shapes of all five d-orbitals are different
If the nitrogen atom has electronic configuration 1s7, it would have energy lower than that of the normal ground state configuration 1s22s22p3, because the electrons would be closer to the nucleus. Yet 1s7 is not observed because it violates.
(a) Heisenberg uncertainty principle
(b) Hund’s rule
(c) Pauli exclusion principle
(d) Bohr postulate of stationary orbits
The configuration 1s2, 2s22p5, 3s1 shows :
(a) excited state of O2–
(b) excited state of neon atom
(c) excited state of fluorine atom
(d) ground state of fluorine atom
The total number of orbitals in a shell with principal quantum number ‘n’ is : 
(a) n2 (b) n + 1
(b) 2n (d) 2n2
Positron is : 
(a) electron with positive charge
(b) a nucleus with one neutron and one proton
(c) a nucleus with two protons
(d) a helium nucleus
The wavelength of visible light is : 
(a) 2000 Å – 3700 Å (b) 7800 Å – 8900 Å
(c) 3800 Å – 7600 Å (d) None of these