2.6 Group 2 Flashcards
Why does atomic radius increase down the group?
More electrons = more electron shells
Why does first ionisation energy decrease down the group?
More electrons = more shielding/greater distance
Why does melting point decrease down the group?
Larger radius= lower charge/volume ratio= reduced attraction= less energy needed.
What is the general equation for the reaction of Mg-Ba with water?
M + 2H20 ➡️ M(OH)2 + H2
Why does reactivity increase as you go down the group?
Ionisation energies decrease
Does solubility of the hydroxides increase or decrease down the group?
Increases
What is the use of calcium hydroxide?
Used in agriculture to neutralise acid soils.
Does solubility of the sulfates increase or decrease down the group?
Decreases
What is the use of magnesium hydroxide?
Used in some ingestion tablets as an antacid. (Milk of magnesia)
Why does the BaCl have to be acidified?
To get rid of any sulfites or carbonates
What is the test for sulfate ions?
Add acidified barium chloride to the solution
What is a positive result for sulfate ions?
White precipitate of barium sulfate.
What is the use of barium sulfate?
Barium meals for X-Rays
Magnesium hydroxide is said to be…?
Sparingly soluble
Why is barium sulfate useful?
It’s insoluble
