group 2 Flashcards
Why does the 2nd ionisation energy of group 2 metal decrease down the group
Number of protons increase but this is outweighed by
Atomic radius increases going down the group these highest energy electrons are held further out the nucleus
Th group 2 elements increase in size going down the group so there is more shielding from inner shells
Explain why calcium has higher melting point than barium
In group 2 the ions get bigger
This means there is a weaker attraction between the sea of delocalised electrons and the metal cations
The metallic bonds are weaker, descending the group and more easily overcome
Therefore the melting and boiling point decrease down the group
What is the reaction with liquid water for group 2 elements
- Mg
- Ca
The reactivity of group 2 elements increases going down the group
Very slow reaction with Mg
More vigorous and with Ca, bubble and mixture will heat up
What is magnesium hydroxide used for
Used as indigestion remedy to neutralise stomach acid
What is barium sulfate and what is the use of barium sulfate in medicine
Insoluble white soil
For x rays
Disadvantage - highly toxic
How do you test for sulfate ions SO2-4
Add BaCl2
The result - white precipitate
Negative result - no visible change
Conclusion for positive result - sulfate ions present as barium sulfate has been produced
Conclusion for negative result - no sulfate ions present
What is a feature of Mg (OH)2
Sparingly soluble
What is a feature of Ca(OH)2
Sparingly soluble
What is a feature of Sr(OH)2
More soluble
What is a feature of Ba(OH)2
Completely dissolves
What happens to the solubility of hydroxides as you go down group 2
Increases
What happens to the solubility of sulfates as you go down group 2
Decreases
What is a feature of MgSO4
Completely dissolved
What is a feature of CaSO4
Fairly soluble
What is a feature of SrSO4
Sparingly soluble
