set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

Which of the following pairs is/are correctly matched?

1. Isotopes : Atoms with same atomic number but different atomic mass
2. Isobars : Atoms with same number of neutrons but different atomic number
3. Isotones : Atoms with same mass number but different atomic number

a) 1 and 2 only

b) 1 only

c) 1, 2 and 3

d) 2 only

Question : 2

The number of molecules in one mole of a gas is

a) 6.023 × 10²¹

b) 6.023 × 10²²

c) 6.023 × 10²³

d) 6.023 × 10²⁰

Question : 3

Which of the following have equal number of neutrons and protons?

a) Deuterium

b) Fluorine

c) Hydrogen

d) Chlorine

Question : 4

The chemical symbol for barium is

a) Ba

b) Be

c) B

d) Bi

Question : 5

Which of the following is not a part of an atom?

a) Proton

b) Neutron

c) Electron

d) Photon

Question : 6

What is the mass number of an element, the atom of which contains two protons, two neutrons and two electrons?

a) 4

b) 6

c) 2

d) 8