Halogens

Room temp: F

pale yellow gas

Room temp: Cl

Green gas

Room temp: Br

Red- brown liquid

Room temp: I

grey solid

Go down group

Atomic radius increases

more electrons

more shells

bigger atomic radius

B.P down the group increases

more electrons

stronger the VDW forces of attraction in between molecules

bigger atoms have more electrons

more energy to overcome

Electronegativity decreases

Bigger the atom, the weaker the electronegativity

F2 has highest electronegativity

small atomic radius

stronger the attraction between the nucleus and outer electron

less shielding

Displacement reactions

Cl2 (aq)

KCl(aq) = no reaction

KBr(aq) = orange solution of Br2 (aq)

KI (aq) = brown solution of I2(aq)

Displacement reactions

Br2 (aq)

KCl(aq) = no reaction

KBr (aq) = no reaction

KI (aq) = brown solution of I2 (aq)

Displacement reactions

I2 (aq)

KCl (aq) = no reaction

KBr (aq) = no reaction

KI (aq) = no reaction

…

Cl2(aq) + 2KBr(aq) —> 2KCl(aq) + Br2(aq)

…

Cl2(aq) + 2Br-(aq) —> 2Cl-(aq) + Br2(aq)

…

Cl2(aq) + 2KI(aq) —> 2KCl(aq) + I2(aq)

…

Cl2(aq) + 2I-(aq) —> 2Cl-(aq) + I2(aq)

…

Br2(aq) + 2KI(aq) —> 2KBr(aq) + I2(aq)

…

Br2(aq) + 2I-(aq) —> 2Br-(aq) + I2(aq)

bleach

2NaOH(aq) + Cl2 —> NaClO(aq) + NaCl(aq) + H2O(l)

2NaOH = cold and dilute

NaClO = bleach ; +1(oxidised)

NaCl = -1 (reduced)

chlorine and water

Cl2(g) + H2O (l)—>< 2H+(aq) + Cl- (aq)+ ClO-(aq)

in the presence of sunlight

Cl2(g) + H2O(l) —>< 2H+(aq) + 2Cl(aq) + ½O2(aq)