Question

Complete the following statements :

(a) Magnesium has 2 valence electrons in the ___ shell.

(b) The valency of nitrogen in $N_2$ molecule is ___

(c) Isotopes have different mass numbers because their nuclei contain different number of ___

(d) Some boron atoms have mass number 10 and some have mass number 11. These boron atoms with different mass numbers are called ___

Answer 1

(a). M
(b). 3
(c). neutrons
(d). isotopes