how do we class group 2 elements
all in s block, all have 2 outer electrons in its valence shell
how will group 2 elements become stable
loose 2 electrons
what happens to the trend in first ionisation energy down group 2
it decreases because
increase in nuclear charge
increased sheilding,
increased. atomic radius
weaker attraction between nucleus and outer electron
what is the trend of atomic radii down group 2
it increases
More electron shells
Increased shielding
less electrostatic attraction between -ve outer electron further from +ve nucleus
what happens to trend in melting point down group 2
it decreases because
no. of shells increases
more inner sheilding
atomic radii increases
less electrostatic attraction so less energy to break electrostatic attraction
what happens to the reactivity down group 2
it increases
more shells increase in sheilding
atomic radii increases
less electrostatic attraction between +ve nucleus and outer electron
easier to loose the electron
what happens to the solubility of group 2 hydroxides down the group
hydroxides become MORE SOLUBLE
What happens to the solubility of group 2 sulphates down the group
sulphates become LESS SOLUBLE
what is Mg(OH)2 normally reffered to as
very insoluble
what is MgSO4 reffered to as
its very soluble
what is BaSO4 reffered to as
it is very insoluble
What is Ba(OH)2 reffered to as
very soluble, can dissociate int Ba2+, and 2OH- ions
What is Ca(OH)2 reffered to as
sparingly soluble
What is the use of Ca(OH)2
“slaked lime” treats acidity in soil, makes pH more neutral - neutralise
What is the use of Mg(OH)2
“milk of magnesia” used to treat indigestion, removes excess stomach acid - neutralise
What is the use of BaSO4
“barium meal” used in diagnosis of stomach problems
It coats tissues and shows up on X-rays
its safe as its insoluble, wont dissolve in body
What is the use of MgSO4
“epsom salt” increases water in intestine
laxative, relives muscle pain
controls seizures
what is the general eq for G2 metal with water
X (s) + 2H2O (l) –> X(OH)2 (aq) + H2 (g)
what is the reaction problem with Mg and water
it reacts very slowly with cold water, reacts well with hot steam
what is Mg eq reaction with hot steam
Mg(s) +H20(g) —> MgO?(s) +H2 (g)
what is the trend of reacitivity with water of group 2 down the group
it increases
How is magnesium used in titanium extraction?
Magnesium reduces titanium(IV) chloride:
TiCl4 + 2Mg→T i+ 2MgCl2
Magnesium acts as the reducing agent.
Why are CaO or CaCO₃ used to remove SO₂ from flue gases?
They react with sulfur dioxide to form calcium sulfite/sulfate, reducing acid rain.
CaCO3+SO2→CaSO3+CO2
CaO+SO2→CaSO3
how to test for sulphate ions
used acidified BaCl2,
Ba +HCl to make acidified BaCl2
BaCl2 +SO42-, a white ppt of BaSO4
