(i) Since the element is placed in 2nd group and 3rd period of the periodic table then this means the element has 2 valence electrons and 3 shells. So it is Magnesium (Mg).
(ii) Its electronic configuration is 2, 8, 2.
(iii) The chemical equation when it burns in the presence of air is
2Mg + O2→ 2MgO
(iv) The balanced equation when this oxide is dissolved in water is
MgO + H2O → Mg(OH)2
Rate this question :