Question

2Mg+02 gives 2Mgo fullform

Answer 1

We must represent the chemical reaction as

2Mg + O2 = 2MgO

because oxygen exists in nature in O2 form only. We cannot find [O] (representation of single oxygen and is called as nascent oxygen) freely in nature.

[O] may obtain form very few chemical reactions and is very unstable combines with other [O] and eventually forms O2 within fraction of seconds.

So, we should not write chemical reaction as Mg + O =MgO

Or we can write as Mg + 1/2O2 = MgO