atomic structure molecules and nuclear chemistry - Category wise Question and Answer Practice Test with Solutions

Question : 16 [CDS]

Which one of the following is not needed in a nuclear fission reactor?

a) Accelerator

b) Coolant

c) Moderator

d) Control device

Question : 17

Which of the following isotopes is used as the standard for atomic mass ?

a) ¹⁶O

b) ¹³C

c) ¹²C

d) ¹H

Question : 18 [NDA]

Which one among the following most correctly determines the atomic number of an element?

a) Number of ions

b) Number of protons and electrons

c) Number of protons

d) Number of nucleons

Question : 19

The number of electrons in an element with atomic number X and atomic mass Y will be

a) (Y – X)

b) (X + Y)

c) (X – Y)

d) X

Question : 20 [NDA]

An oxide of nitrogen has molecular weight 30. What is the number of electrons in one molecule of the compound?

a) 22

b) 15

c) 14

d) 23