Halogen displacement reactions

• The attraction for electrons decreases down the group as the ability of the halogen to gain electrons decreases - outer electrons are further from the nucleus and there is more shielding by inner electrons
• Cl2(aq) + 2Br-(aq) -> 2Cl-(aq) + Br2(aq)
• A competition for electrons where the smaller halogen atom will always win due to its decreased distance and shielding by inner electrons hence a greater pull on outer electrons
• Chlorine displaces bromine from its compound forming an orange-brown liquid to form (bromine) because it is a smaller atom therefore decreased distance from outer electrons to protons in the nucleus and less shielding by inner electrons so a Chlorine has a greater oxidising strength
• Chlorine and bromine displaces iodine from its compound forming a brown liquid to form (iodine) because they are a smaller atom therefore decreased distance from outer electrons to protons in the nucleus and less shielding by inner electrons so Chlorine and Bromine have a greater oxidising strength