The Periodic Table

Question 1

Group 2

Answer 1

Form 2+ ions
Reactivity increases down the group
-ionisation energies decrease
-increasing atomic radius
-increasing shielding effect
-when they react they form cations

Group 2 + water ➡️ hydroxides
Group 2 burn in oxygen ➡️ oxides
Group 2 oxides and hydroxides are bases - they form alkaline solutions in water (pH 12-13) - Mg is the only exception

Group 2 carbonates decompose to form oxides and CO2
Thermal stability decreases down the group

They are used to neutralise acidity
Calcium hydroxide - acidic soils
Magnesium hydroxide - indigestion tablets

Question 2

Group 7

Answer 2

BP and MP decrease down the group due to increasing strength of van der Waals forces as size of RAM increases
Volatility decreases down the group

Get less reactive down the group
The gain an electron so they are reduced
Decrease in atomic attraction
Increase in shielding

Halogens displace less reactive halide ions from solution
Colour changes occur

KCl(colourless) + Cl2(colourless) ➡️ no reaction
KCl(colourless) + Br2(orange) ➡️ no reaction
KCl(colourless) + I2 (brown) ➡️ no reaction

KBr(colourless) + Cl2(colourless) ➡️ orange/red solution formed with organic solvent
KBr(colourless) + Br2(orange) ➡️ no reaction
KBr(colourless) + I2(brown) ➡️ no reaction

KI(colourless) + Cl2(colourless) ➡️ violet/pink formed with organic solvent
KI(colourless) + Br2(orange) ➡️ violet/pink formed with organic solvent
KI(colourless) + I2(brown) ➡️ no reaction

Silver nitrate solution test:
Ag+(aq) + X-(aq) ➡️ AgX(s)

Cl- : White p. Dissolves in dilute NH3
Br- : cream p. Dissolves in concentrated NH3
I- : yellow p. Insoluble in concentrated NH3