Group V||(Chlorine,Bromine and Iodine)

1.They are all diatomic covalently bonded molecules called halogens. Diatomic means that each molecule contains two atoms. The formulae are (Cl2,Br2 and I2).

2.They all either gain one electron from a metal to form an ionic bond or share one electron with a non-metal to form a covalent bond.

3.The halogens exist in solid,liquid and gaseous states at room temperature(onli group of the periodic table).

-Chlorine is a yellow-green gas.

-Bromine is a red-brown liquid.

-Iodine is a dark violet(almost black) solid.When iodine is heated,it sublimes to become a gas with a purple vapour.

-Their reactivity decreases from chlorine to bromine to iodine.

-Metal halides are compounds formed from a metal and a halogen.These are ionic salts which form a giant structure.The halogens will react with transition metals.

aluminium + chlorine -> aluminium chloride
2Al(s) + 3Cl2(g) -> 2AlCl3(s)

-The relative reactivity of the halogens,as described in properties of group V elements,can be shown by displacement reactions(a place of another less reactive halogen from a compound).

-Bromine bubbled through a solution of potassium iodide in water will displace the less reactive iodine,forming iodine and potassium bromide.

bromine + potassium iodide -> potassium bromide + iodine
Br2(g) + 2Kl(aq) ->2KBr(aq) + I2(aq)

-Similarly,chlorine will displace less reactive halogens. Chlorine will displace both bromine and iodine from the halide salt.

chlorine + sodium bromide -> sodium chloride + bromine
Cl2(g) + 2NaBr(aq) ->2NaCl(aq) + Br2(aq)

chlorine + potassium iodide -> potassium chloride + iodine
Cl2(g) + 2KI(aq) ->2KCl(aq) + I2(aq)