Question

octet rule why not valid for Becl2

Answer 1

How many hundredths more than 1.98 is 21

Answer 2

Because all atoms wants have eight electron in its outermost shell in order to stabilize the atom, except or hydrogen, lithium, beryllium, carbon, nitrogen… these are elements that have two or no electron in its outer most shell to stabilize the atom, like this compound BeCl2 beryllium chloride, beryllium atom wants to loses its two electron and give it to chlorine so chlorine have eight electron in its outer shell and beryllium have two electron in its outer shell.
Hopes this helps:)