Question

How do electronegativity values determine the charge distribution in a polar covalent bond?

Answer 1

Answer:

• The polar covalent bonds are formed when the electronegativities of the atoms are different: the most electronegative atoms will pull the electrons with more strength, yielding a partial negative charge over the most electronegative atom and a partial positive charge over the least electronegative atom.

Explanation:

• Covalent bond is the chemical bond where the electrons are shared.

• A polar covalent bond is the covalent bond formed when the electrons are not shared equally.

• Electronegativity is the relative attraction with which the atoms of an element attract the electrons in a covalent bond. The higher the electronegativity the higher the ability of the atoms to attract the electrons.

• Thus, electronegativities are directly responsible for the polar character of the bonds: if the two atoms that form the polar bond have high electronegativity difference, then the most electronegative atom will pull the electrons with more strength, causing a partial negative charge over the most electronegative atom and a partial positive charge over the least electronegative atom. This is a polar covalent bond.

• For example, fluoride, F, is the element with the highest electronegativiy (3.98). Hydrogen has electronegativy 2.2. So The bonds H - F, with electronegativity difference 3.98 - 2.2 = 1.78 are polar covalent bonds because F attracts the electrons more strongly than H does.