Group 2 Flashcards
State the trend in
atomic radius for elements down group 2
- Inc
- More e- shells
State the trend in
first ionisation energy for elements down group
- Dec
- More e- shells
- Shielding occurs
- Outer e- further away from nucleus, less FOA, easier to remove outer e-
State the trend in
reactivity for elements down group 2
- Inc
- React more readily
- Bc ionisation dec
State the trend in
Mp for elements down group 2
- Dec
- Metal ion gets bigger
- Delocalised e- further away from nucleus, less electrostatic FOA, less energy needed to overcome
- Mg is much lower bc crystal structure changes
Write an equation for the reaction of a group 2 metal w/ water
M (s) + 2H2O (l) → M(OH)2 (aq) + H2 (g)
Describe what happens when the group 2 metals react w/ water
- Be - doesn’t react
- Mg - v slowly
- Ca - steadily
- Sr - fairly quickly
- Ba - rapidly
State the trend in
solubility when reacted w/ hydroxide
- Inc
- Mg(OH)<strong>2</strong> = sparingly soluble
State the trend in
solubility when reacted w/ sulfate
- Dec
- BaSO4 = insoluble
What is the test for sulfate ions?
Why is it acidified?
Acidified barium chloride, white ppt forms - BaSO4
W/ HCl to get rid of impurities (sulfites + carbonates) which also form white ppt
How are group 2 metals used for neutralisation?
- Calcium hydroxide (slaked lime) - agriculture to neutralise acid soils
- Magnesium hydroxide - indigestion tablets (antacid) to neutralise excess stomach acid
What is barium sulfate used for?
Barium meal - insoluble so coats tissue, showing up on x-ray
Outline how Mg is used in extracting titanium
- Titanium oxide is converted into titanium chloride by heating w/ C in steam of chlorine gas
- Titanium chlorde is purified by fractional distillation then reduced by Mg in furnace
What is calcium oxide + calcium carbonate used for?
- Remove sulfur dioxide from flue gas - wet scrubbing
- Slurry made by mixing water w/ CaO/CaCO3
- Produces calcium sulfite
