Find the valency of ¹⁴₇N and ³⁵₁₇Cl.

 The atomic number of nitrogen = 7,

No. of protons = 7,

No. of electrons = 7

Electronic configuration = K L                 

                                                   2 5 

Valency = 3                               

Hence, either it will gain three electrons or share 3 electrons to complete its octet.

The atomic number of chlorine = 17,

No of protons = 17,

No of electrons =17

Electronic configuration = K L M

                                                   2 8 7

Hence, it will gain 1 electron to complete its octet.