Question

If z=3 then find it's valency

Answer 1

in the first shell , two electrons are present and in other 1electron is remaining, so that it's valency is 1

Answer 2

same doubt ........................................

here i think do not sure see
Z is a element which atomic no. is three

mean lithium

by electronic configuation you find
2,1 is electronic configuration
that's why the valency is 1