Metallic Bonding

1. In metals, the outer shell is filled through no more than three electrons (loosely bound and given up easily) => great chemical activity and very high electrical conductivity.
2. Outer electron(s) contributed to the crystal like a whole => solid build up of ions with closed shells immersed in a sea of free electrons that are free to move about the crystal under the affect of an electric field.
3. Coulomb attraction force among the ions and the electrons hold the lattice together.