reactivity trends

Question 1

what configuration do group 2 elements have and what charge ions do they make?

Answer 1

s^2 and they from 2+ cations

Question 2

how do group 2 elements’ reactions with oxygen show their reactivities?

Answer 2

the redox reactions become more vigorous down the group

Question 3

how do group 2’s reactions with water show reactivity?

Answer 3

more vigorous down group

Question 4

what is formed between group 2 and oxygen?

Answer 4

white oxides

Question 5

what is formed between group 2 and water?

Answer 5

metal hydroxide

Question 6

what is formed between group 2 and acid?

Answer 6

salt

Question 7

what observation and ph of MgO + water?

Answer 7

no observation 8-9

Question 8

what observation and ph of CaO-BaO + water?

Answer 8

white oxide expands, producing a lot of steam. alkalinity increases down group

Question 9

how does solubility change going down group 2 hydroxides?

Answer 9

increases because more OH- ions are released which makes it more alkaline

Question 10

what uses of group 2 compounds are there?

Answer 10

1. calcium hydroxide neutralises soil
2. calcium carbonate treats indigestion
3. milk of magnesia (magnesium hydroxide) is an antacid

Question 11

how does calcium carbonate work as an antacid?

Answer 11

CaCO3 + 2HCl -> CaCl2 + H2O + CO2

Question 12

what trend exists in BP in the halogens?

Answer 12

boiling point increases down group because the molecules increase - stronger dipole interactions

Question 13

what reactivity trend exists in the halogens and why does it exist?

Answer 13

reactivity decreases down the group

this can be investigated by displacement reactions with other halides and noting colour

Question 14

what is disproportionation?

Answer 14

oxidation and reduction of the same element such as
Cl2 + 2NaOH -> NaCl + NaOCL
Cl2 + H2O HClO + HCl

Question 15

what are the benefits and worries of using chlorine in water treatment?

Answer 15

good: kills bacteria
bad: toxic an chlorinated hydrocarbons can be carcinogenic

Question 16

what is the carbonate ion test?

Answer 16

1. add dilute nitric acid to sample

2. pass gas through limewater

Question 17

what is the test for sulphate ions?

Answer 17

1. barium nitrate solution

2. positive result is white precipitate of barium sulphate

Question 18

what is the test for ammonium ions?

Answer 18

1. a NaOH to the sample and warm
2. test gas with damp red litmus
3. positive result is blue

Question 19

what is the correct order of tests?

Answer 19

1. carbonate ions to prevent further contamination
2. sulphate ions as they would come up in test 3
3. halide