How is electronegativity related to covalent bonding?
atoms must have similar electronegativities in order to share electrons in a covalent bond.
atoms must have very different electronegativities in order to transfer electrons in a covalent bond.
atoms must have similar electronegativities in order to transfer electrons in a covalent bond.
atoms must have very different electronegativities in order to share electrons in a covalent bond.

The following statement explains the relation between electronegativity and covalent bonding:  

Further explanation:

Electronegativity is the inherent tendency of an atom to have an affinity towards the shared pair of electrons. Unlike the ionization energy or electron affinity, it is the property of the atom within a molecule and is dependent upon the nature of the molecule.

A covalent bond is formed by the sharing of electron via overlap of the orbitals of the combining atoms. For effective sharing of electron pairs each atom must be capable of sharing its valence electrons. For this to occur they must have similar electronegativities. If the electronegativity difference is more than the ionic bonding occurs that involves complete transference of electrons. For instance, in case of molecule the electronegativity difference is approximately 2.1. Whenever the difference exceeds 1.8 the bonding is regarded as ionic. This is the reason that sodium chloride is an ionic compound.

An example of a covalent molecule is . Here the bond is polar but the difference in electronegativity does not exceed 1.8 and hence it is regarded as covalent molecule.

Another example of the covalent molecule is methane where the difference in the C-H electronegativities is only 0.4 so it is regarded as a pure covalent molecule. In methane, the carbon is a tetravalent atom and it shares its four electrons by overlap with hydrogen orbitals to form four C-H covalent bonds. The effective overlap is possible because the carbon and hydrogen have similar electronegativities.

Learn more:

1. Molecular shape around the central atoms in the amino acid glycine:

2. Scientific notation:

Answer details:  

Grade: High School

Subject: Chemistry

Chapter: Chemical bonding

Keywords: Electronegativity, electron affinity, covalent bond, ionic bonding, overlap, valence electrons, NaCl, HCl, CH4, a single bond, bonding electrons, and non-bonding electrons.

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