Melting point down a group
Down the group the melting points decrease. The metallic bonding weakens as the atomic size increases. The distance between the positive ions and delocalized electrons increases. Therefore the electrostatic attractive forces between the positive ions and the delocalized electrons weaken.
1st ionisation energy down a group
The outermost electrons are held more weakly because they are successively further from the nucleus in additional shells. In addition, the outer shell electrons become more shielded from the attraction of the nucleus by the repulsive force of inner shell electrons
Reactivity of group 2 metals
increases down the group
What happens when Mg reacts with oxygen?
Mg burns with a bright white flame. MgO is a white solid with a high melting point due to its ionic bonding.
equation when Mg reacts with O2
2Mg + O2 ----> 2MgO
Magnesium with water
Magnesium burns in steam to produce magnesium oxide and hydrogen. The Mg would burn with a bright white flame
equation when Mg reacts with water
Mg (s) + H2O (g) ----> MgO (s) + H2 (g)
Mg with warm water
Mg + 2 H2O ----> Mg(OH)2 + H2 This is a much slower reaction than the reaction with steam and there is no
calcium with cold water
Ca + 2 H2O (l)---> Ca(OH)2 (aq) + H2 (g)
strontium with cold water
Sr + 2 H2O (l)----> Sr(OH)2 (aq) + H2 (g)
Barium with cold water
Ba + 2 H2O (l)----> Ba(OH)2 (aq) + H2 (g)
what reactions are observed when group 2 metals reacts with water
fizzing, (more vigorous down group) the metal dissolving, (faster down group) the solution heating up (more down group) and with calcium a white precipitate appearing (less precipitate forms down group)
Why is titanium is a very useful metal
it is abundant, has a low density and is corrosion resistant – it is used for making strong, light alloys for use in aircraft
How is titanium extracted?
Titanium is extracted by reaction with a more reactive metal Mg Na
Why cant titanium be extracted with carbon
titanium carbide (TiC) it is formed rather than titanium.
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