Question

The valency of an element A is 4. Write the formula of its oxide.

Answer 1

the valency of an element is 4. that means it is 4th A group element. all 4A group elements carbon(C), silicon (Si), lead (Pb), germanium(Ge), tin (Sn). their oxides are CO₂, SiO₂, PbO₂, SnO₂, GeO₂. so the formula of A oxide is AO₂.

Answer 2

The formula of the oxide of an element A whose valency is 4 is AO₂.

• The valency of an element A is 4.
• This implies that element A has 4 valence electrons.
• The valency of oxygen is -2.
• This implies that oxygen gains 2 electrons to complete its octet.
• By the criss-cross method, we get

         ⇒  A        O

         ⇒  4         -2

         ⇒ A₂O₄

• The simplest formula of the oxide of an element A whose valency is 4 is AO₂.

Hence, the formula of the oxide of element A is AO₂.