Extra 40 multiple-choice questions (MCQs) from the chapter:4 "Structure of the Atom" of Class 9 CBSE Science:
Who discovered the electron?
a) J.J. Thomson
b) Ernest Rutherford
c) James Chadwick
d) Niels Bohr
Answer:
a) J.J. Thomson
What is the charge of a proton?
a) Neutral
b) Positive (+1)
c) Negative (-1)
d) None of these
Answer:
b) Positive (+1)
The atomic number of an element is determined by the number of:
a) Neutrons
b) Electrons
c) Protons
d) Nucleons
Answer:
c) Protons
Which of the following is NOT a part of Dalton’s atomic theory?
a) Atoms are indivisible
b) Atoms combine in simple whole-number ratios
c) Atoms can be created and destroyed
d) All atoms of an element are identical
Answer:
c) Atoms can be created and destroyed
Rutherford’s gold foil experiment led to the discovery of:
a) Electron
b) Proton
c) Nucleus
d) Neutron
Answer:
c) Nucleus
Which subatomic particle was discovered by James Chadwick?
a) Electron
b) Proton
c) Neutron
d) Positron
Answer:
c) Neutron
In Bohr’s model, electrons revolve around the nucleus in:
a) Circular orbits
b) Elliptical orbits
c) Random paths
d) Straight lines
Answer:
a) Circular orbits
The mass number of an atom is given by:
a) Number of protons
b) Number of neutrons
c) Number of protons + neutrons
d) Number of electrons + neutrons
Answer:
c) Number of protons + neutrons
The maximum number of electrons that can be accommodated in the K shell is:
a) 2
b) 8
c) 18
d) 32
Answer:
a) 2
What is the valency of oxygen?
a) 1
b) 2
c) 3
d) 4
Answer:
b) 2
The charge on a neutron is:
a) +1
b) -1
c) 0
d) +2
Answer:
c) 0
Which scientist proposed the "plum pudding" model?
a) Rutherford
b) J.J. Thomson
c) Bohr
d) Dalton
Answer:
b) J.J. Thomson
An isotope of an element has:
a) The same atomic number but different mass number
b) The same mass number but different atomic number
c) Different numbers of protons
d) The same number of neutrons
Answer:
a) The same atomic number but different mass number
The atomic number of
carbon
is 6. How many protons are in a neutral carbon atom?
a) 4
b) 6
c) 8
d) 12
Answer:
b) 6
Which element has the atomic number 1?
a) Oxygen
b) Hydrogen
c) Helium
d) Carbon
Answer:
b) Hydrogen
The subatomic particle that revolves around the nucleus is:
a) Proton
b) Neutron
c) Electron
d) Nucleon
Answer:
c) Electron
Which of the following pairs are isotopes?
a) 12C
^{
12}C12C and 14C^{14}C14C
b) 16O^{16}O16O and 16N^{16}N16N
c) 12C^{12}C12C and 16O^{16}O16O
d) 14N^{14}N14N and 14O^{14}O14O
Answer:
a) 12C^{12}C12C and 14C^{14}C14C
Who discovered the nucleus?
a) J.J. Thomson
b) Rutherford
c) Bohr
d) Dalton
Answer:
b) Rutherford
The valency of neon (Ne) is:
a) 0
b) 1
c) 2
d) 3
Answer:
a) 0
How many electrons are present in the L shell of sodium (Na)?
a) 1
b) 2
c) 8
d) 11
Answer:
c) 8
The electrons in an atom are arranged in:
a) A nucleus
b) Fixed orbits
c) The
centre
d) None of these
Answer:
b) Fixed orbits
The number of neutrons in an atom of oxygen-18 is:
a) 8
b) 10
c) 18
d) 16
Answer:
b) 10
Which shell has the highest energy?
a) K
b) L
c) M
d) N
Answer:
d) N
The atomic number of an element is 15. What is its electronic configuration?
a) 2,8,5
b) 2,8,6
c) 2,7,6
d) 2,6,7
Answer:
a) 2,8,5
The charge of an electron is:
a) +1
b) -1
c) 0
d) +2
Answer:
b) -1
Isotopes have different:
a) Atomic number
b) Mass number
c) Number of protons
d) Number of electrons
Answer:
b) Mass number
Bohr’s model explained the stability of:
a) Atoms
b) Molecules
c) Ions
d) None of these
Answer:
a) Atoms
Which scientist gave the first atomic model?
a) Dalton
b) Rutherford
c) J.J. Thomson
d) Bohr
Answer:
a) Dalton
The number of valence electrons in chlorine is:
a) 5
b) 6
c) 7
d) 8
Answer:
c) 7
The smallest particle of an element is:
a) Atom
b) Molecule
c) Proton
d) Electron
Answer:
a) Atom
The atomic mass of helium is:
a) 2
b) 4
c) 6
d) 8
Answer:
b) 4
The outermost shell of an atom is called:
a) Nucleus
b) Core shell
c) Valence shell
d) Inner shell
Answer:
c) Valence shell
The atomic number of
oxygen
is:
a) 6
b) 8
c) 10
d) 12
Answer:
b) 8
The neutron was discovered in the year:
a) 1905
b) 1932
c) 1911
d) 1897
Answer:
b) 1932
The mass of an electron is:
a) Equal to a proton
b) Twice the mass of a proton
c) 1/1000 of a proton
d) 1/1836 of a proton
Answer:
d) 1/1836 of a proton
Elements in the same group of the periodic table have:
a) The same atomic number
b) The same number of neutrons
c) The same valency
d) The same number of protons
Answer:
c) The same valency
Who gave the planetary model of an atom?
a) Dalton
b) Rutherford
c) J.J. Thomson
d) Bohr
Answer:
d) Bohr
The electron configuration of nitrogen (Atomic number 7) is:
a) 2,3
b) 2,5
c) 2,7
d) 2,8
Answer:
b) 2,5
The atomic number of sodium is:
a) 9
b) 10
c) 12
d) 11
Answer:
d) 11
Which of the following is NOT a fundamental particle of an atom?
a) Proton
b) Neutron
c) Electron
d) Positron
Answer:
d) Positron
