Question

if valency of mg is +2 and valency of sulphate (so4)is -2 then the formula of compound formed by these

Answer 1

The formula of the compound formed by these :-

MgSo4

Answer 2

MgSO4. Magnesium Sulphate is an ionic compound that is formed by gaining or losing electrons.

We know the valency of both over here so inter-cross both these valencies to each other.

We see that since both have a valency of two, they get crossed out and the final formula becomes MgSO4.

If either of them did not have a valency of two the other valency could have been written underside the element magnesium or sulphate.

For example, if it had been Aluminum sulphate, that could have been written as (Al)2(SO4)3.