Zusammenfassung der Ressource
The alkaline earth metals
- Loses two electron when they react
- 2+ ions
- atomic radius increases down the group
- Ionisation energy decreases down the group
- Increased shielding
- Valance electron is further away from the nucleus
- Reactivity increases down the group
- Low first and second ionisation energies
- Melting points decrease down the group
- Group 2 metallic structures, with the electrons of their outer shells being delocalised
- Bigger ions=smaller charge/volume ratio
- Electrons are more spread out
- Except for magnesium
- Crystal structure changes
- Group 2 react with water
- Be:
doesn't react
Mg:
VERY slowly
Ca:
steadily
Sr:
fairly quickly
Ba:
rapidly
- Solubility in hydroxide
- Mg is least
soluble
- Barium is most soluble
- Solubility in sulfate
- Mg is most soluble
- Barium is least soluble
- Test for sulfate ions
- Barium chloride is added to the solution
- White precipitate of barium sulfate is formed
- Group 2 compounds neutralise acidity
- Calcium hydroxide neutralises acidic soils
- Magnesium hydroxide is used in indigestion tablets
- H+ +OH- --> H2O
- Barium sulfate in barium meals
- X-rays wont pass through barium sulfate
- Insoluble