Group 2 Flashcards
atomic radius down group 2
increases
1st IE down group 2
decreases
larger atomic radius
more shielding
melting point down group 2
decreases
weaker metallic bonding
larger ions, same delocalised electrons
reactivity down group 2
increases
easier to lose outer electrons
Group 2 reactions with oxygen
2Mg + O2 -> 2MgO
solubility of group 2 hydroxides in water
increase down group (Ba(OH)2 is the most soluble)
use of Mg(OH)2
medicine as an antacid
it is alkaline and can neutralise
this is preferred over Ca(OH)2 in medicine as it will not produce CO2 gas
use of Ca(OH)2
neutralise acidic soils
neutralisation ionic equation
H+(aq) + OH-(aq) -> H2O(l)
solubility of group 2 sulfates in water
decrease down group (MgSO4 is the most soluble)
use of BaSO4
barium meals
it is opaque to x-rays
it is insoluble, so cannot be absorbed into blood
group 2 reactions with water; redox
oxidise to form 2+ ions
M -> M2+ + 2e-
group 2 reactions with water
form metal hydroxide and hydrogen
M + 2H2O -> M(OH)2 + H2
Ba reacts the quickest
group 2 reactions with water down group
fizzing
dissolving of metal
solution heats up
all of these are faster or more extreme down the group
group 2 reactions with steam
M(s) + H2O (g) -> MO(s) + H2
Use of Mg
Reducing agent to extract Ti from TiCl4
why can’t Ti be extracted with carbon?
TiC is formed, not Ti
why can’t Ti be extracted with electrolysis?
it has to be very pure
Step 1 in extraction
TiO2(s) converted to TiCl4(l)
Tio2 + 2Cl2 + 2C -> TiCl4 + 2CO
Step 2 in extraction
TiCl4 purified by distillation in Argon atmosphere
Step 3 in extraction
Ti extracted by Mg in argon atmosphere at 500C
TiCl4 + 2Mg(l) -> Ti(s) + 2MgCl2
Flue gas removal
SO2 can be removed from flue gas by reacting with CO or CaCO3
Make slurry; mix CO or CaCO3 with water and spray on flue gas. produces waste produce Calcium Sulfite
Flue gas removal: CaO (calcium oxide)
CaO(s) + 2H2O(l) + SO2(g) -> CaSO3(s) + 2H2O(l)
Flue gas removal: CaCO3 (calcium carbonate)
CaCO3(s) + 2H2O(l) + SO2(g) -> CaSO3(s) + 2H2O(l) + CO2(g)
