Topic 4a

Question 1

reactivity trend of group 2 metals

Answer 1

increases down the group

the electron is further from the nucleus and there is more shielding

Question 2

trend in solubility of group 2 hydroxides

Answer 2

increases down the group

Question 3

trend in solubility of group 2 sulphates

Answer 3

decreases down the group

Question 4

trend in thermal stability of group 2 nitrates

Answer 4

stability increases
Be is such a powerful polarising ion (charge density) it polarises the NO3- ion so much that only a small amount of energy is needed to break the bond

Question 5

trend in thermal stability of group 2 carbonates

Answer 5

the stability increases down the group
the Be cation is so polarising it polarises the carbonate ion and only a small amount of energy is needed to break the C-O bond

Question 6

reason for flame colours

Answer 6

energy absorbed excites the electrons which are promoted to a higher energy level
they fall back down to ground state and a photo of light is emitted in visible range

Question 7

lithium flame colour

Answer 7

red

Question 8

sodium flame colour

Answer 8

orangey yellow

Question 9

calcium flame colour

Answer 9

brick red

Question 10

strontium flame colour

Answer 10

Crimson red

Question 11

barium flame colour

Answer 11

pale green

Question 12

experiment for thermal stability of nitrates

Answer 12

how long it takes oxygen to be produced (relight glowing splint)
how long it takes brown gas (NO2) to be produced -toxic

Question 13

experiment for thermal stability of carbonates

Answer 13

how long it takes co2 to be produced ( lime water)