A partial negative charge is formed on more electronegative atom in a bond and a partial positive charge is formed at lesser electronegative atom in a bond.
Explanation:
Order of electronegativity: F > O > Cl > N > S > C > H
More electronegative atom in a bond will attract electrons in bond toward itself.
Hence a partial negative charge is formed on more electronegative atom in a bond and a partial positive charge is formed at lesser electronegative atom in a bond.
Delta notation for each bond has been given below.
