CBSE Class 9 - Chemistry - CH4 - Structure of Atom (MCQs)

Structure of Atom

Bohr Model
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MCQs


Q1: Proton was discovered by:

(a) Rutherford
(b) Goldstein
(c) Chadwick
(d) J.J. Thomson


Q2: Canal rays are _______________

(a) negatively charged particles
(b) positively charged particles
(c) beam of neutrons
(d) gamma radiation


Q3: α-particles are ___________

(a) negatively charged particles
(b) positively charged particles
(c) beam of neutrons
(d) gamma radiation



Q4:  An α-particle is _____________

(a) a Hydrogen nucleus
(b) a Helium nucleus
(c) a proton
(d) an electron


Q5: Rutherford's gold foil experiment showed that most of the α-particles passed through the gold foil without any deflection. It indicates that


(a) the nucleus is concentrated at the centre
(b) the nucleus carries a positive charge
(c) there is a lot of empty space in an atom
(d) the nucleus carries the most of the mass


Q6: Two elements X and Y have the same atomic mass but their atomic numbers are 20 and 21 respectively. X and Y are:

(a) isobars
(b) isotones
(c) isomers
(d) isotopes


Q7: In an atom, the mass number of an atom is equal to the number of _________________.

(a) nucleons
(b) protons
(c) electrons
(d) neutrons


Q8: Number of neutrons present in the Hydrogen atom is _______.

(a) 0
(b) 1
(c) 2
(d) 3


Q9: Protium, Deutrium and Tritium are isotopes of ____________.

(a) Rhodium
(b) Sodium
(c) Hydrogen
(d) Helium


Q10: If Z represents the atomic number and A represents the mass number, then the number of neutrons in an atom can be computed as

(a) A + Z
(b) A – Z
(c) Z – A
(d) Z


Q11: If Z represents the atomic number and A represents the mass number, then the number of electrons  in an atom can be computed as

(a) A + Z
(b) A – Z
(c) Z – A
(d) Z


Q12: The electronic configuration of an atom is 2,8,3. The number of valence electrons in the atom is

(a) 13
(b) 10
(c)  3
(d)  8


Q13: The number of electrons in the outermost shell in the atom of an inert element is

(a) 0
(b) 1
(c) 2
(d) 8


Q14: Which one of the following will have the maximum charge/mass ratio?

(a) electron
(b) proton
(c) neutron
(d) α-particle

Q15: The maximum number of electrons that can be accommodated in M shell is:

(a) 2
(b) 8
(c) 18
(d) 32

Answer:
1: (a) Rutherford
2: (b) positively charged particles
3: (b) positively charged particles
4: (b) a Helium nucleus
5: (c) there is a lot of empty space in an atom
6: (a) isobars
7: (a) nucleons
8: (a) 0
9: (c) Hydrogen
10: (b) A – Z
11: (d) Z
12: (c)  3
13: (d) 8
14: (a) electron
15: (c) 18