Question

If there is valency of magnesium is 2 and we know that for writing chemical formulae we have to write their valencies but in magnesium sulphate why it is not written as mgso2 instead of mgso4 because we know that magnesium has 2 valency but why this happens

Answer 1

Because the valancy of Sulphate is also 2 so both are crossed and it is written MgSO4

Answer 2

Bcuz sulphate has valency of -2. So +2 and -2 are balance each other. So it was written as mgso4