Question

Define mono-valent, divalent and trivalent elements with example $$?$$

Answer 1

Hint: First we know a covalent bond is a chemical bond that involves the sharing of electron pairs between atoms and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. The combining capacity of an atom is known as its valency. The number of bonds that an atom can form as part of a compound is expressed by the valency of the element.

Complete answer:
The types of Covalent bonds are single, double, and triple bonds. Single bonds occur when two electrons are shared and are composed of one sigma bond between the two atoms. Double bonds occur when four electrons are shared between the two atoms and consist of one sigma bond and one pi bond.
An atom, ion, or elements with a valence of one (they can either donate or accept two electrons), which can form one covalent bond is called monovalent. Examples for monovalent atoms are Hydrogen, Sodium, Chlorine, etc.
An atom, ion, or elements with a valence of two, is called divalent. Examples for divalent atoms are Oxygen, Magnesium, Sulphur, etc.
An atom, ion, or elements with a valence of three, is called trivalent. Examples for trivalent atoms are Nitrogen, Aluminium, Phosphorous, etc.

Additional information: A sigma bond is the strongest type of covalent bond, in which the atomic orbitals directly overlap between the nuclei of two atoms. Sigma bonds can occur between any kind of atomic orbitals where overlap happens directly between the nuclei of atoms.

Note:
Note that monovalent elements can remove or gain one electron in order to become stable, whereas divalent elements can remove or gain two electrons in order to become stable. The electron pairs sharing in covalent bonds are known as shared pairs or bonding pairs.