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Periodicity, Group 2 & 7 - Coggle Diagram
Periodicity, Group 2 & 7
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Group 2
Solubility of Hydroxides:
Group 2 hydroxides become more soluble down the group. When they aren't soluble they appear as white ppts
Magnesium hydroxide is insoluble Mg(OH)2 -used to treat constipation-
Calcium hydroxide is partially soluble Ca(OH)2
Barium hydroxide is soluble. Ba(OH)2
Melting Points:
melting point decreases down group 2 the metallic bonding decreases as the ions increase in size as the distance between positive ions and delocalised electrons increases.
1st Ionisation energy:
Ionisation energy decreases down the group as the atomic radius increases the outer electron is further away from the nucleus so there is a decrease in nuclear attraction as well as an increase in shielding making it easier to remove the outer electron.
Atomic Radius:
Atomic radius increases down group two due to an increase of shielding lowering nuclear attraction and the increase of shells to hold electrons.
Mg to extract Titanium:
- TiO2 (s) converted to TiCl4 (l) at 900c
- TiCl4 is purified by fractional distillation in an argon environment.
- Ti is extracted by Mg in an argon environment at 500c
TiO2 + 2Cl + 2C --> TiCl4 + 2CO
TiCl4 + 2Mg --> Ti + 2MgCl2
Solubility of sulfates:
Group 2 sulfates gets less soluble down the group
BaSO4 is used as a barium meal before x-rays.
To test for a sulfate:
Add BaCl2 into a solution if sulfates are present a white ppt of BaSO4 will form.
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