Question

How do you use electronegativity values and the chemical formula of a substance to tell if the substance is nonpolar covalent, polar covalent, coordinate covalent, or ionic?

Answer 1

Electronegativity is defined as the measure of the tendency of the atom to attract a bonding pair of electrons. According to the electronegativity difference between the atoms the compound is classified as polar compound or non-polar compounds.

Complete step by step answer:
The covalent compounds are described as those compounds where the atoms are bonded by covalent bonds. The covalent bonds are formed by the mutual sharing of electrons between the atoms. The covalent bonds are formed between the two non-metals.
Nonpolar covalent bonds, where equal sharing of the bonding electrons take place which arise when the electronegativity value of the two atoms are equal. Example: ${H_2}$ in H-H each H atom has an electronegativity value of 2.1, therefore the covalent bond between them is considered nonpolar. The electronegativity difference will be between 0.00 – 0.40.
Polar covalent bonds form between two nonmetal atoms that have different electronegativity values and therefore have unequal sharing of the bonding electron pair. Example: In H-Cl, the electronegativity value of the Cl atom is 3.0, and the H atom is 2.1. The electronegativity difference will be between 0.41 – 1.00.
Coordinate bonds are alternate covalent bonds which are formed by sharing an electron pair from a single atom. Both shared electrons are donated by the same atom. Example: Formation of ammonium ion. The electrons are shared by nitrogen atoms. They are non-polar in nature.
The ionic bond is formed between metal ions and a nonmetal by transfer of electrons. The ionic compounds are highly polar in nature. Example: NaCl. The electronegativity difference is higher than 2.

Note: You must know that in polar covalent bonds and ionic bonds, the electron pair will be moved towards the more electronegativity atom. As a result, one atom obtains a partial negative charge whereas the less electronegative atom obtains partial positive charge.