Question

ma'am pls. explain in detail how to find valency of barium....

Answer 1

first write the electronic configuration of barium .
then the number of electrons present in the outermost shell of barium that helps barium to complete its octet will be its valency.

for example → no of electrons present in the outermost shell of barium are 2 .

so its easy for barium to lose 2 electrons than to gain 6 electrons to complete its octet.
so it loses 2 electrons and completes its octet.

therefore its valency is +2.

hope it helps you