Group 2 elements Flashcards
What are the physical properties of group 2 elements?
- High melting and boiling points.
- light with low densities.
- Form colourless compounds.
What is the electronic configuration?
2 electrons in their outer shells.
What happens to the reactivity going down the group and why?
- Increases down group 2 as the electrostatic attraction between the nucleus and the valence electrons decreases, because the atomic radius and electron shielding both increase.
Reaction with oxygen.
- products formed
- what is oxidised and reduced
Mg as example.
2Mg(s) + O2(g) -> 2Mgo(s)
- All react to form oxides.
- Mg oxidised as ox n. increases from 0 to +2.
- O reduced as ox n. decreases from o to -2.
Reaction with water.
- Products formed.
- What is oxidised and reduced?
use calcium as an example
Ca(s) + 2H20(l)-> Ca(OH)2 (aq) + H2 (g)
- Reacts to form hydroxides and hydrogen gas.
- Ca is oxidised as ox n. increases from 0 to +2.
- H is reduced as ox n. decreases from +1 to 0.
magnesium and steam.
- product formed
Mg(s) + H20 (g) -> MgO(s) + H2(g)
- React to form oxide and hydrogen gas.
metal + acid ->
salt + hydrogen.
reaction between barium and HCl
- balanced equation.
- what is oxidised and reduced.
Ba(s) + 2HCl (aq) -> BaCl2(aq) + H2(g)
- Mg oxidised as ox n. increases from 0 to +2.
- H reduced as ox n. decreases from +1 to 0.
What happens to solubility and alkalinity down the group?
Increases.
When carbonates react with acids what does it form?
salts, H2O and CO2 gas.
Balanced reaction between BaCO3 and HCl.
BaCO3 + 2HCl -> BaCl2 + H20 + CO2
Use of calcium carbonate.
- Calcium carbonate is limestone.
- Used in the building trade, manufacture of glass and steel.
Use of calcium hydroxide.
- Calcium hydroxide is lime.
- Used by farmers and gardeners to neutralise acidic soil.
Use of magnesium hydroxide.
- Used as “milk of magnesia” to relieve indigestion - it neutralises acid in the stomach.
Type of bonding for group 2 metals.
Metallic, strong forces between positive ions and negative delocalised electrons.
