Electronegativity and Covalent Bonds

[Sarah Spalding 3E]

Can someone clarify exactly how electronegativity relates to whether or not a bond that forms is ionic vs covalent? I know that atoms with a greater difference in electronegativity tend to form covalent bonds, but I'm still struggling to explain to myself why that is.

[Girija_3E]

Hi!

I hope this is helpful, but this was my understanding: an atom that has a very high electronegativity means that it has a great ability to attract electrons (these are going to be the elements on the top right corner of the periodic table). When an atom with a very high electronegativity bonds with an atom with low electronegativity (when there is a large difference in electronegativity between the two atoms), they will form an ionic bond. This is because the atom with the lower electronegativity will transfer its valence electron(s) to the atom with the higher electronegativity because its pull is greater. On the other hand, if the difference in electronegativities is not as extreme, they will share electrons, forming a covalent bond.

[Sabrina Dunbar 1I]

When the difference in electronegativity of two bonding elements is greater than 2, then the bond is going to be ionic in character. If the difference in electronegativity is less than 1.5, then the bond is going to be covalent. The above explanation did a good job explaining why this occurs.