Question

X and Z have atomic no. 7 and 9 respectively, write the formula when X combines with Z and justify the answer.

Answer 1

Atomic number of X = 7 (electronic configuration 2, 5)
Atomic number of X = 9 (electronic configuration 2, 7)
Therefore, valency of X = 3 and valency of Z = 1

The formula when X combines with Z is $X{Z}_3$_.