Partial charges occur when partial charges occur when (a) a covalent bond links atoms of two kinds. (b) atoms share electrons unequally. (c) two ions are close togeth

option (b) atoms share electrons unequally.

That is because although the molecule or compound is neutral, some atoms will bear more electron density than others, so the atomes inside the compound that have more electron density will be partially negative while the atoms with less electron density will be partially positive.