Why do atoms form chemical bonds?

Why do atoms form chemical bonds?

Why do atoms form chemical bonds? Or Why Atoms react to each other?

Everything around is made up of matter and matter is composed of compounds. Compounds can be molecules. The molecules are made up of atoms and the molecules are present in three different state of matter i-e solid, liquid and gas around us.

The atoms of all the elements except noble gases have incomplete outermost shell therefore these atoms wants to complete their outermost shell by chemical combination with another atom to become stable in nature like noble gases. The noble gases have complete outermost shell i-e 2 and 8 electrons in their outermost shell. An atom can complete its outermost shell in three ways and it is as follow

By giving valence shell electrons if less than four.

By gaining electrons if there are 5, 6 and 7 electro in their outermost shell.

By sharing valence shell electrons with another atom.