# Metallic Bonds

4.5.NoS Use theories to explain natural phenomena—the properties of metals are different from covalent and ionic substances and this is due to the formation of non-directional bonds with a “sea” of delocalized electrons. (2.2)

4.5.U15 A metallic bond is the electrostatic attraction between a lattice of positive ions and delocalized electrons.

4.5.U2 The strength of a metallic bond depends on the charge of the ions and the radius of the metal ion.

4.5.U3 Alloys usually contain more than one metal and have enhanced properties.

4.5.AS1 Explanation of electrical conductivity and malleability in metals.

4.5.AS2 Explanation of trends in melting points of metals.

4.5.G1 Trends should be limited to s- and p-block elements.

4.5.Aims2 Aim 7: Computer simulations could be used to view examples of metallic bonding.

4.5.AS3 Explanation of the properties of alloys in terms of non-directional bonding.

4.5.G2 Examples of various alloys should be covered.

4.5.Aims1 Aim 1: Global impact of value of precious metals and their extraction processes and locations

4.5.IM1 The availability of metal resources, and the means to extract them, varies greatly in different countries, and is a factor in determining national wealth. As technologies develop, the demands for different metals change and careful strategies are needed to manage the supply of these finite resources.