Why does one atom have a partial negative charge in a polar covalent bond?

Question

That atom is more likely to form ionic bonds.

That atom has a greater attraction for electrons.

That atom has a lesser attraction for electrons.

Answer 1

The atom has a greater attraction for electrons. In a polar covalent bond, the shared pair of electrons is not equally shared between the two atoms involved. One atom has a higher electronegativity, leading to a stronger pull on the electrons and resulting in a partial negative charge on that atom.