U2S2 group 2 Flashcards
What happens to atomic radius down group
- increases
- extra electron shells are added as go down group
What happens to first ionisation energy down group
- decreases
- added shielding and distance from nucleus means easier to lose outer electron
What happens to reactivity down group
- increases
- easier to lose electrons to form positive ions
What happens to melting point down group 2
- General decrease as have typical metallic structures
What happens to oxidation state of group 2 elements when react
Oxidised from state of 0 to +2
What is the reaction for beryllium and magnesium with steam
Metal + steam -> metal oxide + hydrogen
What is the reaction for magnesium, calcium, strontium and barium with water
Metal + water -> metal hydroxide + hydrogen
What is the trend for solubilities of group 2 compounds with a singly charged anion
Increase down group
What is the trend for solubilities of group 2 compounds with doubly charged anions
Decreases down group
What can barium sulfate be used for
- barium meals as coats tissues so can show up on x-ray
How is titanium extracted
- main ore titanium oxide is converted to titanium chloride by heating with carbon in a stream of chlorine gas
- titanium chloride purified by fractional distillation and then reduced by magnesium in a furnace at 1000 degrees
- TiCl4(g) + 2Mg(l) -> Ti(s) + 2MgCl2(l)
How is sulfur dioxide removed from flue gases
- wet scrubbing
- slurry made by mixing calcium oxide or carbonate with water which is sprayed onto flue gases
- sulfur reacts with alkaline slurry to produce calcium sulfite
Equations for wet scrubbing
CaO(s) + 2H2O(l) + SO2 (g) -> CaSO3(s) + 2H2O(l)
CaCO3(s) + 2H2O(l) + SO2 (g) -> CaSO3(s) + 2H2O(l) + CO2(g)
What are other uses of group 2 compounds
- calcium hydroxide = agriculture to neutralise acidic soils
- magnesium hydroxide = indigestion tablets
