Question

An element 'A'reacts with oxygen to form A20.
a) state number of valence electrons in 'A'.
b) to which group of periodic table 'A' belongs?

Answer 1

a) element react with oxygen A2O
hence its means element has valancy 1
hence valence electron is 1

b) group no 1 (s -block )

Answer 2

 Element forms A₂O with oxygen
The valency will be 1 of the element

a) As the valency is 1, it has 1 valence electron.

b) Group no 1