Download 02 Atomic Structure

Q 1.
Which of the following statements is cathode rays?
(a) They produce heating effect
(b) They carry negative charge
(c) They produce X—rays when strike having high atomic masses
(d) None of the above
Q 2.
The correct statement about proton is:
(a) It is. a nucleus of deuterium
(c) It is an ionised hydrogen molecule
Q 3.
(b) It is an ionised hydrogen atom
(d) it is an -particle
The absolute value of the charge on electron was determined by:
(a) J. J. Thomson
(b) R. A. Milikan
(c) Rutherford
(d) Chadwick
Q 4. The highest value of elm of anode rays has been observed when the discharge tube is
filled with:
(a) N2
(b) O2
(c) H2
(d) He
Q 5.
Which of the following statements is incorrect?
(a) The charge on electron and proton are equal and opposite
(b) Neutrons have no charge
(c) The mass of proton and electron are nearly the same
(d) None of the above is incorrect
Q 6.
When a gold sheet is bombarded by a beam of -particles, only, a few of them get
deflected, whereas most go straight, undeflected. This is because:
(a) the force of attraction exerted on -particle by electrons is insufficient
(b) the volume of nucleus is smaller than atom
(c) the force of repulsion acting on fast moving -particle is very small
(d) the neutrons have no effect on -particle
Q 7.
The Rutherford experiment led to the conclusion that:
(a) mass and energy are related
(b) mass and positive charge of an atom are concentrated in its centre as nucleus
(c) neutrons are present in the nucleus
(d) none of the above
Q 8.
Which of the following is true for Thomson’s model of atom?
(a) The radius of an electron can be calculated by using this model
(b) In an undisturbed atom, the electron will be at their equilibrium position, where the
attraction between the cloud of positive charge and the electrons balances their mutual
repulsion
(c) It can explain the existance of protons
(d) None of the above
Q 9.
Rutherford scattering formula fails for very small scattering angles because:
(a) the kinetic energy of -particles is larger
(b) the gold foil is very thin
(c) the full nuclear charge of the target atom is partially screened by its electron
(d) all of the above
Q 10. The conclusions of Rutherford scattering experiment does not include:
(a) -particle can come within a distance of the order of 10-14 m of the nucleus
(b) The radius of the nucleus is less than 10-14 m
(c) Scattering follows Coulomb’s law
(d) The (+) vely charged parts of an atom move with extremely high velocities
Q 11. Choose the incorrect relation on the basis of Bohr’s theory:
(a) Velocity of electron  1/n
(b) Frequency of revolution  1/n3
(c) Radius of orbit  n2Z
(d) Force on electron  1/n4
Q 12. The change in orbital angular momentum corresponding to an electron transition inside
an atom can be:
(a) h/4
(b) h/
(c) h/8
(d) none of these
Q 13. In an X—ray experiment, different metals are used as the target. In each case, the
frequency v of the. radiation produced is measured. If Z = atomic number Which of the
following plots will be a straight line?
(a) v against Z
(b) v against Z
(c) v against Z
(d) None of these
Q 14. In Moseley’s equation [ v = a (Z - b)]:
(a) b depends on metal and a is independent of metal
(b) both a and b are metal dependent
(c) both a and b are independent of metal
(d) a is metal dependent while b is not
Q 15. Which of the following is not the basic postulate of Dalton’s atomic theory?
(a) Atoms are neither created nor destroyed in a chemical reaction
(b) In a compound, the relative number and kinds of atom are constant
(c) Atoms of all elements are alike, including their masses
(d) Each element is composed of extremely small particles called atoms
Q 16. Bohr’s theory is applicable to:
(a) He
(b) Li2+
(c) He2+
(d) None of these
Q 17. The mass of electron moving with the velocity of light is:
(a) 2me
(b) 3me
(c) zero
(d) Can be calculated as  by formula
m
e
me' 
2
v
1  
c
Q 18. Compared to the mass of lightest nuclei, the mass of an electron is only (app.):
(a) 1/80
(b) 1/800
(c) 1/1800
(d) 1/2800
Q 19. The potential energy of an electron present in the ground state of Li2+ ion is :
3e 2
3e 2
3e 2
3e
(a) 
(b) 
(c) 
(d) 
40 r
40 r
40 r
40 r 2
Q 20. A Mo atom in its ground state has a 4d5 5s1 configuration and a Ag atom 4d10 5s1
configuration. This is because a shell which is half filled or completely filled is
particularly:
(a) strongly exchange destabilised
(b) weakly exchange stabilised
(c) weakly exchange destabilised
(d) strongly exchange stabiised
Q 21. An f-shell containing 6 unpaired electron can exchange:
(a) 6 electrons
(b) 9 electrons
(c) 12 electrons
(d) 15 electrons
Q 22. The statement does not belong to Bohr’s model of atom is:
(a) Energy of the electrons in the orbit is quantised
(b) The electron in the orbit nearest to the nucleus is in lowest energy state
(c) Electrons revolve in different orbits around the nucleus
(d) The electrons emit energy during revolution due to the presence of Coulombic forces
of attraction
Q 23. The argument which favours the particulars nature of cathode rays is :
(a) they produce fluorescence
(b) they travel through vacuum
(c) they get deflected by electric and magnetic fields
(d) they cast shadows of objects present in their way
Q 24. Which of the following reactions led to the discovery of neutrons?
(a) 6C14 + 1P1  7N14 + 0n1
(b) 4Be9 + 2He4  6C12 + 0n1
(c) 5B11 + 1D2  6C11 + 0n1
(d) 4Be8 + 2He4  6C11 + 0n1
Q 25. Which of the following pails have identical values of elm?
(a) A proton and a neutron
(b) A proton and deuterium
(c) Deuterium and an a-particles
(d) An electron and -rays
Q 26. Choose the arrangement which show the increasing value of elm for e, p. n and a particle:
(a) n <  < p < e
(b) e < p <  < n
(c) n < p < e < 
(d) p < n <  < e
Q 27. The ground state electronic configuration of nitrogen atom can be represented as:
(a)
(b)
(c)
(d) All of these
Q 28. The electronic configuration with maximum exchange energy will be:
(a) 3d 1xy 3d 1yz 3d 1zx 4s1
(b) 3d 1xy 3d 1yz 3d 1zx 3d 1x2  y 2 3d 1z 2 4s1
(c) 3d xy2 3d yz2 3d zx2 3d x22  y 2 3d 1z 2 4s1
(d) 3d xy2 3d yz2 3d zx2 3d x22  y 2 3d z22 4s1
Q 29. Which of the following will violates Aufbau principle as well as Pauli’s exclusion
principle?
(a)
(b)
(c)
(d) None of these
Q 30. After np6 electronic configuration, the next orbital filled will be:
(a) (n+1)d
(b) (n+1)s
(d) (n + 1)f
(d) none of the above
Q 31. From the discharge tube experiment it was concluded that:
(a) mass of proton is in fraction
(b) matter contains electrons
(c) nucleus contains positive charge
(d) positive rays are heavier than protons
Q 32. The characteristic not associated with Planck’s theory is:
(a) radiations are associated with energy
(b) the magnitude of energy associated with a quantum is proportional to frequency
(c) radiation energy is neither emitted nor absorbed continuously
(d) radiation energy is neither emitted nor absorbed discontinuously
Q 33. Einstein’s theory of photoelectric effect is based on:
(a) Maxwell’s electromagnetic theory of light
(b) Planck’s quantum theory of light
(c) both of the above
(d) none of the above
Q 34. Choose the incorrect statement:
(a) Every object emits radiation whose predominant frequency depends on its
temperature
(b) The quantum energy of a wave is proportional to its frequency
(c) Photons are quanta of light
(d) The value of Planck constant is energy dependent
Q 35. Which of the following transitions are not, allowed in the normal electronic emission
spectrum of an atom ?
(a) 2s1s
(b) 2p  1s
(c) 3d  4p
(d) 5p  3s
Answers
1.
8.
15.
22.
29.
D
B
C
D
C
2.
9.
16.
23.
30.
B
C
B
C
B
3.
10.
17.
24.
31.
B
D
D
B
B
4.
11.
18.
25.
32.
C
C
C
C
D
5.
12.
19.
26.
33.
C
B
C
A
B
6.
13.
20.
27.
34.
B
C
D
C
D
7.
14.
21
28
35.
B
D
D
D
A