Chemical Activity of An Atom-Octet or Duplet RuleCertain elements are chemically active while others are not. Chemically active elements have an incomplete octet in the valence shell of their atoms. Kossel and Lewis (1916) put forward the octet theory of valency to explain the chemical activity of atoms. According to them, elements tend to combine (form chemical bond) with one another to attain the stable electronic configuration of the nearest inert gas (duplet or octet).
The force of attraction that exists between the atoms is known as a chemical bond.
A chemical bond can be formed
- by complete transfer of electrons, e.g. NaCl, MgCl2, CaO, or
- by sharing of electrons, e.g. H2O, NH3, N2, HCl
Lewis structure for different elements are shown in Table
The numbers enclosed within brackets indicate the number of valence electrons.