How do molecular compounds come to have a slight electrical charge

Molecular compounds tend to have slight electrical charge due to atoms of different elements having different values of electronegativity. Electronegativity is the ability of an atom pull on electrons of the bonded atom as well. Due to this pull by nucleus of bonded atoms, the less electonegative atom tends to lose its electrons to the more electronegative atoms, causing the atoms to become slightly positively and negatively charged respectively.