Final answer:
The greater the electronegativity difference between two bonded atoms, the greater the percentage of ionic character in the bond.
Step-by-step explanation:
The greater the electronegativity difference between two bonded atoms, the greater the percentage of ionic character. Electronegativity measures an atom's ability to attract shared electrons. When there's a small difference in electronegativity between two atoms, electrons are more equally shared, leading to a covalent bond. However, when there's a large difference, the more electronegative atom will pull electrons toward itself more strongly, creating a polarized bond with a higher ionic character. In the extreme, when the electronegativity difference is very large, as typically seen between metals and nonmetals, electrons are transferred, not shared, resulting in an ionic bond.
According to the Pauling electronegativity scale, as the difference in electronegativity increases, bonds tend to have more ionic characteristics. For polar covalent bonds, the unequal sharing generates partial charges on the atoms, leading to a bond dipole. In contrast, a truly ionic bond is viewed as having full charges on the resulting ions.