9 group 2 Flashcards
what happens to atomic radius down group 2?
increases
what happens to 1st ionisation energy down group 2?
decreases
why does 1st and 2nd ionisation energy decrease down group 2?
more shielding so the outer electrons are further from the nucleus
what happens to melting points down group 2?
general decrease
what happens when group 2 elements react with water?
form metal hydroxide
what is the equation for the reaction with Sr and H2O?
Sr (s) + 2H2O (l) -> Sr(OH)2 (aq) + H2 (g)
what happens to the solubility of group 2 hydroxides down the group?
solubility increases
what happens when you react Mg with steam?
more vigorous reaction
Mg (s) + H2O (g) -> MgO(s) + H2 (g)
what happens to group 2 sulfates down the group?
solubility decreases
how do you test for sulfates?
- add HCl
- add BaCl
- white precipitate present=positive result
why do you add HCl before BaCl when testing for sulfates?
to remove any carbonates that could give a false result
what can group 2 compounds neutralise?
acids
what can neutralise acidic soil?
Ca(OH)2
what can neutralise stomach acid?
Mg(OH)2
what is the ionic equation for neutralisation?
H+ (aq) + OH- (aq) -> H2O (l)
