Practice Atomic Structure MCQs

Question 1

Which subatomic particle carries a negative charge and orbits the nucleus of an atom?

Accepted Answer

C. Electron

Answer

A. Proton

Answer

B. Neutron

Answer

D. Positron

Question 2

What is the charge on a neutron?

Accepted Answer

C. Neutral

Answer

A. Positive

Answer

B. Negative

Answer

D. Variable

Question 3

The number of protons in the nucleus of an atom is called its what?

Accepted Answer

B. Atomic number

Answer

A. Mass number

Answer

C. Isotope number

Answer

D. Valency

Question 4

Who proposed the "plum pudding" model of the atom?

Accepted Answer

B. J.J. Thomson

Answer

A. Ernest Rutherford

Answer

C. Niels Bohr

Answer

D. John Dalton

Question 5

Isotopes of an element differ in the number of which particle?

Accepted Answer

C. Neutrons

Answer

A. Protons

Answer

B. Electrons

Answer

D. Positrons

Question 6

What is the maximum number of electrons that can occupy the first (K) shell of an atom?

Accepted Answer

A. 2

Answer

B. 8

Answer

C. 18

Answer

D. 32

Question 7

Rutherford gold foil experiment led him to conclude that most of an atom mass and positive charge is concentrated in what?

Accepted Answer

B. Nucleus

Answer

A. Electron cloud

Answer

C. Valence shell

Answer

D. Orbital cloud

Question 8

According to the Bohr model, electrons revolve around the nucleus in fixed paths called what?

Accepted Answer

B. Shells or energy levels

Answer

A. Orbitals

Answer

C. Subshells

Answer

D. Quanta

Question 9

What is the electronic configuration of a neutral chlorine atom (atomic number 17)?

Accepted Answer

B. 2, 8, 7

Answer

A. 2, 8, 8

Answer

C. 2, 7, 8

Answer

D. 2, 6, 9

Question 10

The mass number of an atom is the sum of which two quantities?

Accepted Answer

B. Protons and neutrons

Answer

A. Protons and electrons

Answer

C. Neutrons and electrons

Answer

D. Electrons only

Question 11

Which quantum number describes the shape of an atomic orbital?

Accepted Answer

B. Azimuthal quantum number

Answer

A. Principal quantum number

Answer

C. Magnetic quantum number

Answer

D. Spin quantum number

Question 12

Carbon-14, used in radiocarbon dating, is an isotope of carbon differing from carbon-12 by how many neutrons?

Accepted Answer

B. Two

Answer

A. One

Answer

C. Four

Answer

D. Six

Question 13

The Aufbau principle used for writing electron configurations states that electrons occupy orbitals in order of what?

Accepted Answer

B. Increasing energy

Answer

A. Decreasing energy

Answer

C. Random order

Answer

D. Atomic number only

Question 14

According to Heisenberg uncertainty principle, which pair of properties of an electron cannot both be measured with complete precision simultaneously?

Accepted Answer

B. Position and momentum

Answer

A. Charge and mass

Answer

C. Spin and charge

Answer

D. Energy and charge

Question 15

Which rule states that electrons occupy degenerate orbitals singly before pairing up?

Accepted Answer

B. Hund's rule

Answer

A. Pauli exclusion principle

Answer

C. Aufbau principle

Answer

D. Octet rule

Practice MCQs