group 2 Flashcards
(22 cards)
describe the trend in first ionisation energy from Mg to Ba
decreases
-number of principle energy levels increase
-shielding increases
-weaker attrcation between outer e- and nucleus
describe the trend in reactivity with water as you go down the group
increases
-size of atom increases as you go down
-increase in shielding
-loses electrons more readily/easily
describe the trend in solubility of hydroxides in water as you go down the group
increases
-Mg(OH)2 is not very soluble
-Ba(OH)2 is very soluble
describe the trend in atomic radius from Mg to Ba
increases
-increase in principle energy levels
-more shielding
-weaker attraction between outer e- and nucleus
write an equation for the reaction of Mg with steam. include state symbols
Mg(s) + H2O(g) —> MgO(s) + H2(g)
describe what barium meal is used for
x-ray of the digestive system
magnesium hydroxide is only sparingly soluble in water. use this to explain why the reaction of magnesium with water stops after a short time
Mg(OH)2 forms a thin layer on the surface of magnesium, which stops the water from coming into contact with magnesium
describe the melting point from Mg to Ba
decreases
-size of ion increases
-weaker attraction between positive ions and delocalised electrons
describe a test to shoe the presence of sulphate ions in an aqueous solution. give the results of the test when performed on separate aqueous solutions of magnesium chloride and magnesium sulphate. write equations for any reactions giving a positive test
-nitric acid and barium chloride solution
-white ppt
-Ba^2+(aq) + SO4^2-(aq) —> BaSO4(s)
explain why a solution being tested for sulphate ions needs to be acidified first
to remove carbonates that would form a ppt
what is magnesium hydroxide used for
to treat indigestion
describe the trend in solubility of sulphates down the group
decreases
-Mg is soluble
-Ba is insoluble
explain why barium can be swallowed even though barium meal is toxic
barium sulphate is insoluble
write a general equation for the reaction between water with a group 2 metal using M to represent the metal
M(s) + 2H₂O(l) —> M(OH)₂(s) + H₂(g)
what is calcium hydroxide used for
neutralising acidic soil
Test for hydroxide ions
MgCl2 solution added to solution
if hydroxide ions present white ppt of Mg(OH)2 forms
test for magnesium ions
NaOH is added
-if Mg ions is present white ppt of mg(OH)2 formst
test for sulphate ions
add acidified barium chloride solution
-if sulphate ions present white ppt of BaSO4 forms
test for Ba ions
add sulphuric acid
if Ba ions present white ppt of BaSO4 forms
test to acidify sulphatew unknown solution
2H+ + CO3^2- —> CO2 + H2O
what is CaO used for
used in flue gas desulfurisation
write the equation for the extraction of titanium and what is used as a reducing agent?
TiCl4(g) + 2Mg(l) —> Ti(s) + 2MgCl2(l)
Magnesium is used as a reducing agent
