Calculate the percentage composition of the various elements in `MgSO_(4)`.

Explanation

`"Mol. Mass of "MgSO_(4)=24+32+4xx16=120`
`%" of Mg"=("No. of parts by mass of Mg")/("Mol. mass of "MgSO_(4))xx100=(24)/(120)xx100=20%`
`%" of S"=("No. of parts by mass of S")/("Mol. mass of "MgSO_(4))xx100=(32)/(120)xx100=26.67%`
`%" of O"=("No. of parts by mass of O")/("Mol. mass of "MgSO_(4))xx100=(64)/(120)xx100=53.33%`