Group 2

Use of Barium Sulfate

as a Barium meal for X ray imaging

Use of Magnesium Hydroxide and why

antacids → Mg less likely to react with stomach acid

Use of Ca(OH)₂

neutralise acidic soil

Use of MgSO₄

epsom salts

CaSO₄

Gypsum/Plaster

Barium Sulphate is toxic, so how is it used in a barium meal?

It does not dissociate in the body (INSOLUBLE)

Calcium + water forms what

slight white precipitate

Trend of reactivity down the group?

increases down the group, outer 2 electrons further from nucleus, more electron shielding, easier to remove outermost electrons

Trend in first ionisation energy down the group?

decreases down the group, atomic radius increases, electron shielding increases, less energy needed to remove outer electron

hydroxides are __ down the group

more

sulphates are __ soluble down the group

less

melting and boiling points down group

decrease, as atomic radius increases, charge density decreases, electrostatic attraction between metal cation and delocalised electrons get weaker

flue-gas desulphurisation why?

petrol engines will not work efficiently if sulphur is present

CaO + SO₂ → ???

CaSO₃

CaCO₃ + SO₂ →

CaSO₃ + CO₂

test for sulphate/barium ions

acidify tests with HCl to remove impurities, add BaCl₂ , if sulphate ions present white ppt of BaSO₄ forms, as it is insoluble

test for magnesium ions

add NaOH, if white ppt forms then positive test

extraction of Ti 2 equations

TiO_² + 2Cl₂ + C→ TiCl₄ + CO₂
TiCl₄ + 2Mg → Ti + 2MgCl₂