Explain the formation of a chemical bond.
A chemical bond is the attractive force that holds various constituents (atoms, ions, etc.) together in different chemical species. Except for noble gases, no element exists as an independent atom in nature.
The formation of a chemical bond was explained by Kössel and Lewis based on the inertness of noble gases. Lewis pictured the atom as a positively charged 'Kernel' (the nucleus plus inner electrons) and an outer shell accommodating a maximum of eight electrons. This octet of electrons represents a particularly stable electronic arrangement.
Atoms combine to attain this stable noble gas configuration. This occurs through the sharing of electron pairs between atoms to form covalent bonds, or by forming an aggregation of positive and negative ions in an ionic compound.
Explanation
The answer defines a chemical bond as the attractive force holding atoms together. It then uses the Kössel-Lewis approach to explain why atoms combine: to achieve the highly stable octet electronic arrangement characteristic of noble gases, either by sharing electrons (covalent bonding) or forming ions (ionic bonding).