2.2.2 structure types

Group 0 elements

Elements: H2 O2 N2 F2 Cl2 Br2 I2 S8 P4 Compounds: non-metal with non-metal

Elements: Si, diamond, graphite, graphemes Compounds: SiO2

Compounds: metal and non-metal

Elements: Metals

Individual atoms with very weak forces between them

Lots of individual molecules with weak forces between the molecules (the atoms within molecules are joined by covalent bonds)

Lattice structure in which all atoms are joined together in a giant network by covalent bonds

Lattice structure of positive and negative ions The ions are held together by the strong electrostatic attraction between the + and - ions, known as ionic bonding

Lattice structure of metal atoms where the outer shell electrons from each atom are delocalised There is a strong attraction between the positive nucleus of the atoms and the cloud of negative delocalised electrons (metallic bonding)

None

Covalent (within molecules)

Covalent

Ionic

Metallic

Gives number of atoms of each type in one molecule E.g. glucose C6H12O6 Each molecule contains 6C, 12H and 6O atoms

Just the symbol E.g. Ar

Gives ratio of atoms in substance E.g. glucose CH2O Ratio of C:H:O atoms is 1:2:1

Gives ratio of atoms in substance E.g. SiO2 Ratio of Si:O atoms is 1:2

Gives ratio of ions in substance E.g. MgCl2 Ratio of Mg2+:Cl- ions is 1:2

Just the symbol E.g. Fe

Very low due to very weak forces between atoms

The heavier the atoms, the stronger the forces between the atoms, resulting in higher M&BP

Low due to weak forces between the molecules The atoms within the molecules are held together by strong covalent bonds, but these do not break when molecules melt/boil