Group 7

• Halogens = elements in group 7; gain one electron to form halide ions (-1 charge)
• Halogens reactivity decreases down the group (they react by gaining one electron, so the further the outer shell is from the positive attraction of the nucleus the harder it is to gain an electron)
• Halogens melting + boiling points increase down the group (harder to melt)
• Group 7 elements = toxic so reactions have be completed in a fume cupboard
• Group 7 elements = non-metals
• group 7 elements = diatomic molecules = two atoms joint together (HONG7)
• chlorine = cl2
• highly reactive group 1 + group 7 elements combine to make unreactive stable products

  sodium + chloride = sodium chloride
• sodium chloride = table salt/white solid
• Chlorine kills bacteria
• volatile = turns into gas quickly
• X = halogens = diatomic (The metal for X in an equation must have ₂)
• F₂ = pale yellow gas
• Cl₂ = yellow-green gas
• Br₂ = Orange-brown liquid
• I₂ = purple solid
• with the increase in size of the atom the reactivity decreases