1.37 draw a diagram to represent the positions of the ions in a crystal of sodium chloride.

SODIUM CHLORIDES LATTICE:

- The ions are placed oppositely in their lattice. The ions are closely packed together and are stuck in their position because of the attraction of their oppositely charged ions.

1.36 describe an ionic crystal as a giant three-dimensional lattice structure held together by the attraction between oppositely charged ions

IONIC CRYSTAL:

- The ions in the lattice are closely packed together.
- The lattice is only held together by the oppositely charged ions. A good example is sodium chloride. You must be able to draw this for the exam. Go to 1.37 to see the lattice of NaCl.

1.35 understand the relationship between ionic charge and the melting point and boiling point of an ionic compound

RELATIONSHIP:

- The higher the difference between charges the greater the melting and boiling points as their is a stronger force of attraction.

1.34 understand that ionic compounds have high melting and boiling points because of strong electrostatic forces between oppositely charged ions

Already done in 1.33:

HIGH POINTS:

- They have high melting and boiling points because of the strong electrostatic forces of attraction. This means a lot of energy is required to overcome these bonds

1.33 understand ionic bonding as a strong electrostatic attraction between oppositely charged ions

IONIC BOND:

- Is a strong electrostatic attraction between oppositely charged ions. This gives ionic compounds high melting and boiling points.

1.32 explain, using dot and cross diagrams, the formation of ionic compounds by electron transfer, limited to combinations of elements from Groups 1, 2, 3 and 5, 6, 7

ELECTRON TRANSFER:

- In dot and cross diagrams it doesn't matter what element has a dot or cross you just have to make sure that one element either gains or loses electrons. In this case sodium is a cation and chlorine an anion.

1.31 deduce the charge of an ion from the electronic configuration of the atom from which the ion is formed

FROM ELECTRONIC CONFIGURATION:

- It is easy to work out the charge from the electronic configuration mainly because you simply need to work out the quickest route. For example if an ion had an electronic configuration of 2.8.1 it is quicker for the atom to lose an electron rather than it gaining seven electrons. The ion has a charge of 1+.

- Again if the electronic configuration was 2.8.7 then it is quicker to gain electrons rather than losing seven electrons. The ion has a charge of 1-.

1.30 recall the charges of common ions in this specification

COMMON IONS:

You should be able to recall these ones.

- Cation:

- Group 1:

Li +

Na +

K +

- Group 2:

Be 2+

Mg 2+

Ca 2+

- Anions:

- Group 6:

O 2-

S 2-

- Group 7:

F -

Cl -

Br -

1.29 understand oxidation as the loss of electrons and reduction as the gain of electrons

OXIDATION:

- Is when an atom loses electrons.

REDUCTION:

- Is when an atom gains electrons.

1.28 describe the formation of ions by the gain or loss of electrons

IONS:

- For ions to be formed atoms either gain or lose electrons to form charged particles known as ions.
- These ions are strongly attracted to one another. This is because of the + and the - charges.