Group 2 - Alkaline Earth Metals
- Created by: Kenzia Campbell
- Created on: 14-12-12 14:52
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- Group 2 - Alkaline Earth Metals
- Lose two electrons when they react becoming 2+ ions
- All have two electrons in outer shell
- Lose two outer electrons to have the ideal electronic structure
- Atomic Radius increases down the group.
- Due to extra electron shells dpwn the group.
- Ionisation energy decreases down the group.
- Extra shells shield outer electrons from nuclear force of attraction.
- Extra shells mean electrons are further away from nucleus
- Each element down group has an extra electron shell.
- Reactivity increases down the group.
- Ionisation energies decrease
- The easier it is to remove electrons, the more reactive the element.
- Melting points decrease down the group.
- Metalic structures - delocalised electrons in outer shell.
- Smaller volume/charge ratio and delocalised electrons become spread out.
- Reduced force of attraction between the sea of delocalised electrons and the positive ions.
- Mg has lower than expected M.Pt because of the 'more open' lattice arrangement.
- Oxidised when they react. From 0 to 2+
- Hyrdoxides increase in solubility and sulfates decrease in soulbility down the group.
- Barium sulfate used as barium meals in medicine - opaque to xrays and safe as it is insoluble.
- Calcium Hydroxide - neutrilise soils
- Magnesium hydroxide used in indegestion tablets.
- Test for sulfate ions.
- Acidified BaCl2 added to solution.
- If sulfate ions are present white precipitate of barium sulfate is formed.
- Lose two electrons when they react becoming 2+ ions
- Metalic structures - delocalised electrons in outer shell.
- Smaller volume/charge ratio and delocalised electrons become spread out.
- Reduced force of attraction between the sea of delocalised electrons and the positive ions.
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