What happens when the nucleus of one atom attracts a pair of shared electrons more strongly than the nucleus of the other atom in the bond?

If a molecule is polar as a result of a polar covalent bond, which end is positively charged and which end is negatively charged?

A. The electrons move closer to the more electronegative atom.

B. The more electronegative atom is - and the other end is +.

When the nucleus of one atom attracts a pair of shared electrons more strongly than the nucleus of the other atom in the bond, it creates a polar covalent bond. In a polar covalent bond, the electron density is unequally distributed between the atoms.

The atom with the stronger nucleus attracts the shared electrons closer to its side, acquiring a partial negative charge, denoted as δ-. This atom is referred to as the electronegative atom.

Conversely, the other atom, with the weaker nucleus, has a partial positive charge, denoted as δ+. This atom is referred to as the electropositive atom.

Therefore, in a polar covalent bond, one end of the molecule is positively charged (δ+) and the other end is negatively charged (δ-).

When the nucleus of one atom attracts a pair of shared electrons more strongly than the nucleus of the other atom in a bond, it creates a polar covalent bond. In this type of bond, there is an uneven distribution of electrons, causing one end of the bond to have a partial negative charge (δ-) and the other end to have a partial positive charge (δ+). This is because one atom is pulling the shared electrons closer to itself, resulting in a charge imbalance within the molecule.

To determine which end is positively charged and which end is negatively charged, you can look at the electronegativity values of the atoms involved in the bond. Electronegativity is a measure of an atom's ability to attract electrons in a chemical bond. The atom with the higher electronegativity attracts the shared electrons more strongly and gains a partial negative charge, while the atom with the lower electronegativity gains a partial positive charge.

For example, in a bond between hydrogen (H) and chlorine (Cl), chlorine has a higher electronegativity than hydrogen. Therefore, chlorine attracts the shared electrons more strongly, resulting in a partial negative charge on the chlorine atom (Cl^-) and a partial positive charge on the hydrogen atom (H+).

In summary, the end of a polar covalent bond that is positively charged (δ+) corresponds to the atom with the lower electronegativity, while the end that is negatively charged (δ-) corresponds to the atom with the higher electronegativity.