Group 2 Flashcards
Atomic radius in group 2
As you go down atomic radius increases as more electron shells are added
First ionisation energy in group 2
Decreases down group 2 as there is more shielding and electrons are further away from the nucleus so there is less attraction and its more easier to remove an electron
Reactivity down group 2
Increases because first ionisation energy decreases
Melting points in group 2
decrease down group 2 as going down the group the metal ions get larger and so there is a larger ionic radius and the further away the delocalised electrons are from the nucleus there is less attraction so less energy needed to break the bonds
Magnesium is very low as the crystal stricture if different
Reaction with water
Oxidised from 0 to +2
Form metal hydroxide and hydrogen
Solubility
Singly charged negative ions increase in solubility going down the group to ( hydroxide )however doubly charged negative ions decrease of (sulphate)
Order of solubility in hydroxides
Magnesium least soluble, Barium most soluble
Order of solubility in sulphates
Magnesium most soluble, barium least soluble
Test for sulfate ions
Add to a solution containing sulphite ions and a white precipitate should form
Solution needs to be acidified with HCL to get rid of excess sulphites
What is the ionic equation for neutralisation
H+ + OH- =. H20
Use of calcium hydroxide
Agriculture to neutralise acid soils
Use of magnesium hydroxide
Help with indigestion by neutralising stomach acid
Use of barium sulphate
Barium meals to diagnose problems as it helps tissues show up on X rays as barium sulphate is opaque to x rays
Use of magnesium
Extracting titanium
Titanium oxide is converted into titanium chloride by heating it. with carbon in chlorine gas
The titanium chloride is then purified in fractional distilation and reduced by magnesium
