Describe the difference between ionic, covalent, and metallic bonding.
Ionic bonding describes the electrostatic forces of attraction between a metal and a non-metal ion, which are oppositely charged. For example, with NaCl, Na loses an electron to become Na+ and Cl gains this electron to become Cl-. These oppositely charged ions are attracted to each other, and they arrange themselves into a giant ionic lattice. A covalent bond is where two atoms are bound together by a shared pair of electrons. Sharing this pair of electrons will usually mean that each atom is able to fill its outer shell. For example, if we have a two Cl atoms, both of which are one electron away from having a full outer shell, they can fill their outer shell by sharing their last unpaired electron. This forms a Cl2 molecule, with both Cl atoms bound together by a covalent bond. Metallic bonding is the electrostatic forces of attraction between metal ions and a delocalised sea of electrons. For example, if we have a sample of magnesium, then each atom will lose its 2 outer electrons, to become Mg2+ ions, and the electrons will go into the delocalised sea of electrons. The electrostatic forces of attraction between the Mg2+ ions and the electrons constitutes metallic bonding.
