AP BIOLOGY

Detailed explanation-1: -In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bond and is sometimes called an unshared pair or non-bonding pair. Lone pairs are found in the outermost electron shell of atoms. They can be identified by using a Lewis structure.

Detailed explanation-2: -For each molecule, there are different names for pairs of electrons, depending if it is shared or not. A pair of electrons that is shared between two atoms is called a bond pair. A pair of electrons that is not shared between two atoms is called a lone pair.

Detailed explanation-3: -CH4 does not has a lone pair because every electron in valence shell of carbon atoms is shared with Hydrogen atoms.

Detailed explanation-4: -Lone pairs have the greatest repelling effect because they are closer to the nucleus of the central atom compared to the bonding pairs, therefore they repel other lone pairs greater compared to bonding pairs.