1. Chemical Properties

2. Syllabus Statements 3.3 Chemical properties
3.3.1 Discuss the similarities and differences in the chemical properties of elements in the same group.
3.3.2 Discuss the changes in nature, from ionic to covalent and from basic to acidic, of the oxides across period 3.

3. The IB expect you to be able to answer questions about:
Group 0 – the noble gases
Group I – the alkali metals
Group VII – the halogens

4. Group VII – the halogens
Fluorine – yellowish gas

5. Chlorine – pale yellow-green gas

6. Bromine – red-brown liquid (orange in solution)

7. Iodine – purple/black crystalline solid

8. The halogens are coloured (learn the colours!)
They exist as diatomic elements, X2
Their melting and boiling points increase as you go down the group (gas liquid solid)
They are very reactive
Reactivity decreases as you go down the group (why?)
They may form ionic compounds with metals, or covalent compounds with other non-metals.

9. Reaction with group I metals
Halogens react with group I metals to form an ionic halide
The halogen gains one electron from the metal to form a halide ion with a charge of 1-
Electrostatic forces hold the halide ion and the metal ion together