Halogens (Group 7)

• Halogens are non metals.
• The halogens are found in Group 7.
• The colour of the halogens gets darker as you go down the group.
• At room temperature, they have all three states of matter within the group.
• The elements have decreasing energy as you go down the group.
• Fluorine and chlorine are gases.
• Bromine is a liquid.
• Iodine and astatine are solids.
• The density trend of the halogens is that they increase as you go down the group.
• A more reactive halogen will ‘displace’ a less reactive halogen from their salt.
• The halogens become less reactive as you go down the group because the electron to be gained from another element is further from the nucleus.
• Each molecule contains two halogen atoms joined by a single covalent bond.
• he melting points and boiling points of the halogens increase going down group 7. 
• as you go down group 7:

  the molecules become larger

  the intermolecular forces become stronger

  more energy is needed to overcome these forces