Electronegativity

Key Questions

It can determine if a molecule is polar or not...

Explanation:

Electronegativity difference between two atoms in a bond can determine what type of bond is used. Note that this usually only applies to covalent and ionic bonds.

The general rule is that:

$\Delta \text{EN">2, "the bond is ionic}$

$0.5 \le \Delta \text{EN"<2, "the bond is polar covalent}$

$\Delta \text{EN"<0.5, "the bond is non-polar covalent}$

Source:

https://www.chemteam.info/Bonding/Electroneg-Bond-Polarity.html

$\text{Electronegativity is conceived to be the ability......}$
Electronegativity is conceived to be the ability of atom involved in a chemical bond to polarize electron density towards itself. There are various scales, of which the Pauling scale was the earliest, and it is still most widely used. Pauling originally based his scale on ionization energies, and electron affinities. He then normalized the scales so that they gave values roughly between $0 - 4$.