Final answer:
Electronegativity differences between atoms determine the ionic or covalent character of a chemical bond. Larger differences typically lead to more ionic bonds, while smaller differences result in covalent bonds, especially between nonmetals. Polar covalent bonds have partial charges due to uneven sharing of electrons.
Step-by-step explanation:
The relationship between electronegativity and the character of a chemical bond, whether ionic or covalent, is fundamental to understanding chemical bonding. As the difference in electronegativity between two atoms increases, the bond they form tends to have more ionic character. When atoms have similar electronegativities, they share electrons more equally and form covalent bonds.
However, when one atom has a much higher electronegativity than the other, it attracts the shared electrons more strongly, resulting in an ionic bond. Bonds between two nonmetals are generally covalent, whereas bonds between a metal and a nonmetal are often ionic. The polarity of a covalent bond is also affected by electronegativity differences; atoms with greater differences form bonds with more polar character, with the atom having higher electronegativity gaining a partial negative charge.