Experiment 4.2 Chemistry Form | 4

Reactivity decreases down Group 17: Cl > Br > I Chlorine can displace bromine & iodine; bromine can displace iodine only.

2M(s) + 2H₂O(l) → 2MOH(aq) + H₂(g) (Alkali metal + water → metal hydroxide + hydrogen) experiment 4.2 chemistry form 4

| Halogen \ Halide | KCl | KBr | KI | |----------------|-----|-----|-----| | Chlorine water | No reaction | Turns orange (Br₂) | Turns brown (I₂) | | Bromine water | No reaction | No reaction | Turns brown (I₂) | | Iodine water | No reaction | No reaction | No reaction | Reactivity decreases down Group 17: Cl > Br

To investigate the reactivity of Group 1 elements (Li, Na, K) with water & oxygen. Potassium reacts violently

Wear goggles & use small pieces only. Potassium reacts violently!

To determine the reactivity trend of Group 17 (chlorine, bromine, iodine).