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31 Cards in this Set
- Front
- Back
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how many electrons on thuer 2 outer shell does the elements in group 2 have have |
2 |
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what happens to the atomic radius down the group |
it increases since it has more shells of electrons |
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what happens to the ionisation energy down the group |
decrease |
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what happens to the melting point down the group |
decrease |
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why do elements in group 2 have high melting points |
metallic structure have + ions and - electrons have strong attraction and requires lots of energy to break the bonds |
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what happens to attraction between the + ions and electrons going down the group |
metal ions get bigger so larger ionic radius radius the further away the electrons are from the nucleus so the attraction gets weaker |
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why does the reactivity increase down the group |
first ionisation energy decrease and it's easier to lose electrons going down the group |
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what is the general formula for oxidation state |
M=M2+ +2e- |
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what happens when magnesium burns in steam |
it produces magnesium oxide and hydrogen and Mg would burn in white flame Mg (s) + H2O (g) = MgO (s) + H2 (g) |
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what happens when magnesium reacts with warm water |
Mg + 2 H2O = Mg(OH)2 + H2
it is slower than the reaction with steam and there's no flame |
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what is the equations for calcium strontium barium reacting with cold water |
• Ca + 2 H2O (l)= Ca(OH)2(aq) + H2(g) •Sr + 2 H2O (l) =Sr(OH)2(aq) + H2(g) • Ba + 2 H2O (l) =Ba(OH)2(aq) + H2(g) |
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when hydroxides is produced is makes the water alkaline so what would you observe going down the group |
•fizzing, (more vigorous down group)
•the metal dissolving, (faster down group) •the solution heating up (more down group) • calcium a white precipitateappearing (less precipitate forms downgroup) |
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what happens to magnesium when it burns in oxygen |
The group 2 metals will burn in oxygen.Mg burns with a bright white flame.
2Mg + O2 = 2MgO MgO is a white solid with a high meltingpoint due to its ionic bonding. Mg will also react slowly with oxygen without a flame |
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explain why it is important to clean Mg ribbon with emery paper |
If testing for reaction rates with Mg and acid, an un-cleaned Mgribbon would give a false result because both the Mg and MgOwould react but at different rates
Mg + 2HCl = MgCl2 + H2 MgO + 2HCl = MgCl2 + H2O |
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why is titanium a useful metal |
abundant, low density , corrosion resistant, can be used for tennis racket and aircraft |
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how is Ti extracted |
by reaction with more reactive metal |
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what are the step for Ti extraction |
1. TiO2(solid) is converted to TiCl4(liquid) at 900°C 2. The TiCl4is purified by fractional distillation in an Aratmosphere. 3. The Ti is extracted by Mg in an Ar atmosphere at 500°C |
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Explain why Ti can't be extracted by carbon |
Titanium cannot be extracted with carbonbecause titanium carbide (TiC) is formed
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Explain why Ti can't be extracted by electrolysis |
Titanium cannot be extracted byelectrolysis because it has to be very pure.
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Why is Ti expensive |
• The expensive cost of the Mg
• batch process which makes it expensive because theprocess is slower • requires more labour and the energy is lost when thereactor is cooled down after stopping •High temperatures • expensive due to the Ar, and the need toremove moisture
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does Group 2 hydroxides become more soluble down the group. |
yes |
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Ca(OH)2 (describe solubility)
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is sparingly soluble and solution is used as lime water Ca(OH)2 (aq) + CO2 (g)= CaCO3 (s) + H2O(l) |
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Ba(OH)2 (describe solubility)
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dissolves to produce a strongly alkaline solutions Ba(OH)2 (S) + aq= Ba2+ (aq) + 2OH-(aq) |
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what is Ca(OH)2 used for |
It is used in agriculture to neutraliseacidic soil
safe to use cause it's a weak alkali |
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what is Mg(OH)2 used for |
used in medicine to neutralise excess acid in thestomach and to treat constipation.
Mg(OH)2 + 2HCl = MgCl2 + 2H2O |
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Does Group 2 sulphates become more soluble down the group
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NO *BaSO4 is least soluble |
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what is the full equation for formation of the precipitate |
SrCl2(aq) + Na2SO4(aq) = 2NaCl (aq) + SrSO4(s)
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what is the ionic equation for formation of the precipitate
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Sr2+ (aq) + SO42-(aq)= SrSO4(s).
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what is BaSO4 is for |
medicine as a ‘Barium meal’ given to patients who need x-rays of their intestines
even though Barium compounds are toxic it issafe to use here because of its low solubility |
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what is the test of sulphate ion |
BaCl2 solution acidified with hydrochloric acid is used as a reagent totest for sulphate ions.
Ba2+ (aq) + SO42-(aq)= BaSO4(s). *white precipitate forms |
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what happens when HCl acid with carbon impurties |
white Barium carbonate precipitate and so give a false result. You could not used sulphuricacid because it contains sulphate ions and so would give a false positive result
2HCl + Na2CO3 = 2NaCl + H2O + CO2 |
