Indroduction
In this post, you will learn the MCQs of Atoms and Molecules. This MCQs are very important for your exams.

1. In a molecules of hydrogen, ________ atoms and molecules exist together.
a) 1
b) 2
c) 3
d) 4
Answer. (b) 2 

2. Phosphate is a type of 
a) monovalent anion
b) divalent cation
c) trivalent anion 
d) divalent anion
Answer. (c) trivalent anion 

3. The chemical formula of a compound using zinc and phosphate ions is 
Answer. 

4. The number of molecules of phosphorus (P4) present in 31 grams of phosphorus is 

Answer. 

5) The molar mass of ozone is 
(a) 48 u
(b) 32 u
(c) 16 u
(d) 24 u
Answer. (a) 48 u

6) Which of the following is not correct about molecules?
(a) Molecules are stable as compared to atoms.
(b) Homoatomic molecules are the molecules of the element.
(c) Molecules can exist independently.
(d) Molecules can't be divided.
Answer. Molecules can't be divided.

7) The concept of indivisibility of atom was given by
(a) Dalton
(b) Proust
(c) Lavoisier
(d) JJ Thomson
Answer. (a) Dalton

8) The mass ratio of hydrogen and oxygen in hydrogen peroxide (H₂O₂) is
(a) 1:8
(b) 1:16
(c) 8:1
d) 32:1
Answer. (b) 1:16

9. Which of the following is not correct about mole concept?
(a) Mass of one mole of the substance is called molar mass
(b) Mole of substance is the amount of substance which contains 6.022 × 10²⁰ particles.
(c) Mass of one mole of atoms of an element is equal to gram atomic mass of the element.
Answer. (b) Mole of substance is the amount of substance which contains 6.022 × 10²⁰ particles.

10. Which of the following elements exists in liquid form at room temperature?
(a) Fe
(b) N
(c) Hg
(d) Na
Answer. (c) Hg