Chapter 8 - Reactivity trends

Question 1

What is the most common reaction in group two metals?

Answer 1

redox reactions

Question 2

What do the group two elements react with oxygen to form?

Answer 2

metal oxides

Question 3

What do the group two elements react with water to form?

Answer 3

alkaline hydroxide x(OH)2

Question 4

what does a metal and an acid produce?

Answer 4

salt and hydrogen

Question 5

how does reactivity of group two change down the group?

Answer 5

it increases

Question 6

why does the reactivity increase down group two?

Answer 6

the attraction between the nucleus and the outer electrons decreases, increasing atomic radius and increase in shielding

Question 7

how does the solubility,ph and alkalinity of the group two hydroxides change down the group?

Answer 7

all increases

Question 8

What is the test for carbonates?

Answer 8

Add dilute nitric acid
positive test = fizzing

Question 9

What is the test for sulfates?

Answer 9

Add aqueous barium nitrate or barium chloride
positive test = white precipitate

Question 10

what is the test for halides?

Answer 10

add aqueous silver nitrate
bromide = cream
chloride = white
iodide = yellow

Question 11

how can you tell the halides apart?

Answer 11

Add aqueous ammonia
chloride = soluble in dilute NH3
bromide = soluble in conc NH3
iodide = insoluble in NH3

Question 12

What is the sequence of the tests?

Answer 12

1) carbonates
2) sulfates
3) halides

Question 13

why is this sequence of tests important?

Answer 13

• sulfate not halide ions fizz with dilute acid
• barium carbonate forms a white precipitate
• silver sulfate and silver carbonate form precipitates

Question 14

What is the test for ammonium ions?

Answer 14

add aqueous sodium hydroxide and warm the solution
positive test = moist pH indicator will turn blue

Question 15

At RTP what do the halogens exist as?

Answer 15

diatomic molecules

Question 16

describe and explain the change in boiling point of the halogens

Answer 16

increases down the group, due to more electrons which increase the strength of London forces

Question 17

what are the most common type of reaction of the halogens

Answer 17

redox

Question 18

what colour does chlorine, bromine and iodide then in water?

Answer 18

Cl - pale green
Br - orange
I - brown

Question 19

which halogen changes colour in cyclohexane and to what colour?

Answer 19

iodine turns violet

Question 20

describe and explain the change in ionisation energy in ionisation energy of the halogens?

Answer 20

ionisation energy increases because atomic radius increases, shielding increases and there is less nuclear attraction to capture an electron from another species

Question 21

what is disproportionation?

Answer 21

a redox reaction in which the same element is both oxidised and reduced