INORGANIC CHEM - GROUP 2 Flashcards
How many electrons do group 2 elements lose when they react?
2
What is the charge of group 2 ions?
2+
How does atomic radius change down group 2?
- increases
- more shells
State the trend in 1st ionisation energy down group 2
decreases down group 2
Explain the trend in 1st ionisation energy down group 2
- atoms get larger (more shells)
- more shielding
- outer electrons are further away from the nucleus which means that there are weaker forces of attraction between nucleus and outer electrons so its easier to lose the outer electrons
State the trend in reactivity down group 2
increases down group 2
Explain the trend in reactivity down group 2
- atoms get larger (more shells)
- more shielding
- outer electrons are further away from the nucleus which means that there are weaker forces of attraction between nucleus and outer electrons so its easier to lose the outer electrons, the easier it is to lose electrons, the more reactive the element
State the trend in melting and boiling points down group 2
generally decrease down group 2
Explain the trend in melting and boiling points down group 2
- metal ions get larger going down the group
- delocalised electrons further away from nuclei
- weaker electrostatic forces of attraction between delocalised electrons and +ve metal ions
- so less energy required to break metallic bonding
Mg + 2H2O (l) -> ?
Mg(OH)2 + H2
Mg + H2O (g) -> ?
MgO + H2
Ca + 2H2O -> ?
Ca(OH)2 + H2
Sr + 2H2O -> ?
Sr(OH)2 + H2
Ca + 2H2O -> ?
Ca(OH)2 + H2
State the trend in solubility of group 2 hydroxides
increases down group 2
State the trend in solubility of group 2 sulfates
decreases down group 2
Describe the solubility of Mg(OH)2
sparingly soluble
What is Ca used for?
- Ca(OH)2 is used in agriculture to neutralise acid soils
- CaO and CaCO3 are used to remove SO2 - CaO (s) + 2H2O (l) + SO2 (g) -> CaSO3 (s) + 2H2O (l) or CaCO3 (s) + 2H2O (l) + SO2 (g) -> CaSO3 (s) + 2H2O (l) + CO2 (g)
What is Mg used for?
- Mg(OH)2 is used in some indigestion tablets as an antacid to neutralise excess stomach acid
- used as part of the process of extracting Ti from its ore - TiCl4 (g) + 2Mg (l) -> Ti (s) + 2MgCl2 (l)
What is Ba used for?
- barium meals
- BaSO4 is opaque to x-rays so its used in barium meals to help diagnose problems with organs which normally wouldn’t show up on x-rays due to the fact that x-rays pass through soft tissue
