The chemical formula of an oxide of an element is A2O5 state the Valency of A also write the chemical formula of its chloride

a) Valency of A=+5

b) Chemical formula of its chloride=ACl5

Explanation:

(a) Let the valency of element A be x, then 2x + 5 (-2) = 0

As oxegen has a valency of = -2 and overall the compound must be neutral

x=10/2

So, x = valency of element A = 5

(b) (b) As valency of element A is 5 and valency of chlorine is - 1,

So, the formula of chloride of A is ACl5.