understand covalent bonding

• covalent bonding usually occurs between atoms of two non metals
• a covalent bond is formed when an electron is shared between the atoms
• these electrons come from top energy level of atoms
• lone pair


  non binding pair of electrons
• dative bonds(coordinate covalent bond)


  in some covalent molecules, both sharing electrons come from one atom
• covalent bonds can be formed when atoms share more than one pair of electrons, eg. oxygen atoms
• the double bond between the oxygen are formed by two shared pair of electrons