Chemistry - CHEMICAL BONDING Question with Solution | TestHub

The structure of a covalent molecule is related to the number of electrons in the outermost shell of the central atom. The atoms are bonded to each other in a molecule by the sharing of pair of valence shell electrons. Electron pairs repel each other and try to stay as far away as they can. The most stable arrangement of a given number of electron pairs is the one that minimizes the repulsion among them. The shape of a covalent molecule is decided by the orientation of shared pair of electrons in the valence shell of the central atom. This is the basic idea of VSEPR theory.

Presence of lone pair of electrons on central atom gives rise to more repulsion in lone pair bond pair electrons and thereby, contraction in bond angles due to repulsion between lone pair of electrons and bond pair of electrons. The repulsion and contraction in bond order follow:

L.P. – L.P. > L.P. – B.P. > B.P. – B.P.