group 2 Flashcards
trend of atomic radius of group 2 metals
The Group II elements increase in size going down the group. This is because each elements going down the group has an additional filled electron shell in comparison to the element above it.
explain the melting point of group 2 elements in terms of their structure and bonding
therefore form metallic bonds and exist as giant metallic structures. In general this means Group II elements have high melting points.
Descending Group II the ions get bigger. This means the attraction between the ‘sea’ of delocalised electrons and metal ions is weaker and the metallic bonds are weaker descending the group. Therefore the melting point decreases going down the group.
Magnesium is an anomaly. It has the lowest melting point of Group II but there is no straight forward reason.
trend of group 2 metals with liquid water
increases down the group
Mg is least reactive
Ba is most reactive
reactions become more violent down the group
trend in ionisation energy of group 2 metals
Both the 1st and 2nd ionisation energies decrease going down Group II. This is because the outer most electrons are held increasingly further away and so less energy is needed to overcome the attraction between the nucleus and the outer 2 electrons.
reaction of Mg with water
Mg(s) + 2H2O(l) → Mg(OH)2(aq) + H2(g)
very slow
mg(OH)2 used to neutralise stomach acid
reaction of elements Mg-Ba with liquid water trend
The reactivity of Group 2 elements increases going down the group. This means Mg is the least reactive and Ba is the most reactive. This means the reactions with water become more violent as the group is descended.
what’s the use of mg is the extraction of titanium from TiCl4
Once purified, titanium chloride is reduced by magnesium to extract the titanium.
what are the solubilities of the hydroxides of the elements Mg-Ba with water
Mg(OH)2 sparingly soluble
Ca(OH)2 sparingly soluble
Sr(OH)2 more soluble
Ba(OH)2 completely dissolved
what is the use of Mg(OH)2 in medicine
Magnesium Hydroxide can also be called ‘Milk of Magnesia’ and is used as an indigestion remedy to neutralise stomach acid.
what’s the use of Ca(OH)2 in agriculture
used in agriculture to neutralise acidic soils
what is the use of CaO or CaCO3
remove SO2 from flue gases
what are the relative solubilities of the sulfates of the elements Mg-Ba in water
MgSO4 completely dissolved
CaSO4 fairly soluble
SrSO4 sparingly soluble
BaSO4 insoluble
what is the use of BaSO4 in medicine
absorbs x-rays
allows digestive system to be photographed by feeding patients BaSO4 allowing x-rays to be absorbed so images of organs can be obtained
however it is highly toxic
However it is perfectly safe to feed to patients because it is so insoluble it cannot dissolve and pass through cell membranes into body tissue.
