Question

State the reasons for chemical bonding between two atoms and the methods involved for achieving the same. State how ‘duplet and octet’ rules are involved for an atom to achieve stable electronic config. 

Answer 1

The driving force for atoms to combine is related to the tendency of each atom to attain stable electronic configuration of nearest noble gas. For an atom to achieve stable electronic configuration it must have;Either two electrons in its outermost shell (if it is the first shell- nearest noble gas – He) – Duplet rule.

OR 

Eight electrons in its outermost shell (if it is not the first shell – all noble gases other than He have eight electrons in their outermost shell) – Octet rule.

Methods for achieving chemical bonding 

A stable electronic configuration for two combining atoms, resulting in chemical bonding between them is achieved by following two ways.

1. Electron transfer : This involves transference of valence electrons from one atom (metal) to another (non-metal) leading to the formation of electrovalent or ionic bond. This results in the formation of electrovalent or ionic compound.

2. Electron sharing : This involves sharing of pairs of electrons between two atoms (both non-metals). This leads to the formation of covalent bond. The compound so formed is called a covalent compound.