group 1 and 2

Question 1

explain why Ca nitrate needs a higher temp than Mg nitrate for decomposition

Answer 1

Ca2+ has larger ionic radius and more shielding; so lower polarising power; so less distortion of covalent bonds in the nitrate ion

Question 2

explain how colours in a flame test are produced in terms of electronic transitions

Answer 2

electrons excited to higher energy level by heat; light emitted as they return to ground state

Question 3

trend in solubility of hydroxides down group 2

Answer 3

increases (milk of magnesia)

Question 4

trend in solubility of sulfates down group 2

Answer 4

decreases (barium sulfate white precipitate)