Fluorine - Pale yellow gas
Chlorine - Greenish gas
Bromine - Red-brown liquid
Iodine - Black solid
Bigger going down the group because each element above has one extra filled main level of electrons compared with the one above it.
The ability of an atom to attract electrons towards itself within a covalent bond.
Decreases going down the group because the atomic radius increases down the group. (more shells = more shielding = weaker forces)
They increase going down the group because the atoms have more electrons and this makes the Van der Waals forces between the molecules stronger.
The oxidising ability of the halogens increases going up the group.
Halogens will react with metal halides in solution so that the halide in the compound will be displaced by a more reactive halogen.
It increases because the ionic radius increases going down the group, making it easier to lose electrons due to weaker forces.
- Drops of HCl are added to solid sodium chloride
- Steamy fumes of hydrogen chloride can be seen
- The solid product is sodium hydrogensulfate.
NaCl(s) + H2SO4(l) -> NaH2SO4(s) + HCl (l)
False. No oxidation states have changed and chloride is too weak to reduce the sulfur. It is only an acid-base reaction
(- Drops of HCl are added to solid sodium bromide?)
- Steamy fumes of hydrogen bromide and brown fumes of bromine can be seen
NaBr(s) + H2SO4(l) -> NaHSO4(s) + HBr(g)
2H+ +2Br- + H2SO4(l) -> SO2(g) + 2H2O(l) +Br2(l)
-1 +6 +4 0
The reactions are exothermic and some of the bromine vaporises
- Steamy fumes of iodine
- Bad egg smell of hydrogen sulfide gas
- Yellow solid sulfur
- Colourless sulfur dioxide
- (Drops of HCl are added to solid sodium iodide?)
NaI(s) + H2SO4(l) -> NaHSO4 (s) + HI(g)
8H+ + 8I- + H2SO4(l) -> H2S(g) + 4H20(l) + 4I2(s)
-1 +6 -2 0
True. Iodide ions are better at reduction
- 0 Solid yellow sulphur
No precipitate (fluoride does not react with metal halides
- White precipitate
- A further test reveals that it dissolves in dilute ammonia
- A cream precipitate
- It dissolves in concentrated ammonia
- A pale yellow precipitate
- It is insoluble in concentrated ammonia
Cl2(g) + H20(l) -> HClO(aq) + HCl(aq)
0 <- +1 -1
2Cl2(g) + 2H2O(l) -> 4HCl(aq) + O2(g)
pale green colourless
To add solid sodium (or calcium) chlorate which dissolves in water to form chloric acid
NaClO(s) + H2O -> Na+ (aq) + OH-(aq) + HClO(aq)
The equilibrium shifts to the left and the HClO is removed as ClO- ions
Sodium chlorate which is an oxidising agent
A disproportionation reaction
Cl2(g) + 2NaOH(aq) -> NaClO(aq) + NaCl(aq) +H2O(l)
0 +1 -1