Given, M is a metal
(i) Electrovalent bond exits between M and O because the bond is formed between a metal and non-metal due to oppositely charged ions.
(ii) Number of electrons in the outer most shell of M is 1. It is so because the valency of O is -2 and as 2 atoms of M combine with O to form M2O, hence we can say that M has 1 valence electron.
(iii) M belongs to group 1 [1A] because there is 1 electron in the outer most shell.