What are octet and duplet rules? How do elements attain octet?

Explanation

Octet rule was proposed by G.N.Lewis. According to this rule "The atom of an element combines with another atom to have eight electrons in its outermost shell". An atom having 8 electrons in its outermost shell is least reactive or most stable. If there is only one shell, then stability is attained by having 2 electrons in the shell and this is called duplet rule. Element attains octet in the following ways: (i) by losing or gaining electrons. (ii) by sharing electrons with other atoms.