Question

$M$ is a metal above hydrogen in the activity series and its oxide has the formula $M_{2}O$. This oxide when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity. In the above context answer the following:
How many electrons are there in the outermost shell of $M$?

Answer 1

The valency of O is$-2$. As $2$ atoms of M are combined in $M_{2}O$ the valency of M is $+1$. Hence M has $1$ electron in its valence shell.