Meaning of Covalent
The adjective covalent is used in the field of chemistry to describe the bond generated between atoms that share pairs of electrons. It also qualifies as covalent that which has at least one covalent bond .
It is important to remember that particles that have an electrical charge and are made up of a non-neutral molecule or atom are called ions.
Ions, according to the octet rule enunciated by the American Gilbert Newton Lewis in 1916, tend to use eight electrons to complete the last energy levels and thus achieve stability in their configuration.
Atoms, to respect the octet rule , can use different types of chemical bonds to join. Among them is the covalent bond, which involves sharing electrons at the last level. This type of bond requires that the difference in recorded electronegativity between the atoms be less than 1.7.
Covalent bonds develop between atoms of different nonmetals and between atoms that belong to the same nonmetal. Covalently bonded atoms share their electron pairs in the molecular orbital.
These atoms can share between one and three pairs of electrons in a covalent bond: therefore, the bonds can be single, double or triple, depending on the case.
If the bond occurs between equal atoms, with an electronegativity difference of less than 0.4, a nonpolar covalent bond is obtained . On the other hand, if the bond is developed by atoms of different elements that have an electronegativity difference greater than 0.4, it is a polar covalent bond.