The valencies of two elements A and B are given below :
`{:("Element",,"Valency"),(A,,1+),(B,,2+):}`
(i) What is formula of sulphate of A ?
(ii) What is the formula of nitrate of B ?

Explanation

(i) Formula of sulphate of A

Thus, the formula of sulphate of element A is `A_(2)SO_(4)`.
(Please note that the element A of valency 1 is like sodium. So, that sulphate `A_(2)SO_(4)` may be sodium sulphate, `Na_(2)SO_(4)`).
(ii) Formula of nitrate of B

Thus, the formula of nitrate of element B is `B(NO_(3))_(2)`
[It should be noted that the element B of valency 2 is like magnesium, so that the nitrate `B(NO_(3))_(2)` may be magnesium nitrate, `Mg(NO_(3))_(2)`]