Topic 6- Group 7

Question 1

Recall the colour and physical state of chlorine at room temperature

Answer 1

Gas at room temperature and is a yellow-green colour

Question 2

Recall the colour and physical state of bromine at room temperature

Answer 2

Liquid at room temperature and is a red-brown colour

Question 3

Recall the colour and physical state of iodine at room temperature

Answer 3

Solid at room temperature and is a dark purple colour

Question 4

What is a pattern of the physical properties as you go down the group

Answer 4

Trend of state, gas to liquid to solid as you go down the group. The colours become darker as you go down the group

Question 5

Describe chemical test for chlorine

Answer 5

Damp blue litmus paper turns red and then bleaches white if chlorine is present, or damp starch iodine paper turns blue/black

Question 6

Describe uses of halogens

Answer 6

Bleaching agents and killing bacteria

Question 7

What forms when halogens react with metals

Answer 7

They form salts called metal halides

Question 8

Product of metal (sodium) + halogen (chlorine)

Answer 8

(metal halide) = Sodium Chloride

Question 9

Describe reactions of the halogens, chlorine, bromine and iodine, with metals to form metal halides

Answer 9

The reaction between sodium (a metal) becomes less vigorous as we move DOWN group 7. Chlorine will have the most vigorous reaction whereas iodine will have a slower reaction

Question 10

What happens when halogens react with metals- e

Answer 10

The halogens will gain one electron to form an ionic bond.

Question 11

What can halogens, chlorine, bromine and iodine form which dissolves in water

Answer 11

The halogens can form hydrogen halides which dissolve in water to form acidic solutions,
H+ ions make them acidic.

Question 12

What determines a hydrogen halides reactivity

Answer 12

The reactions with water, this determines their acidity- their ease at losing H+ ions.

Question 13

Describe the reactivity of halogens, Chlorine, Bromine and Iodine, as shown by their displacement reactions with halide ions in aqueous solutions

Answer 13

Halogens are more reactive when they have less shells because they want to gain electrons- the electrostatic force of attraction is less as its closer to the nucleus

Question 14

What is a displacement reaction

Answer 14

A chemical reaction which a more reactive element displaces a less reactive element from its compound

Question 15

Displacement reaction eg-

What is formed from potassium bromide+chlorine

Answer 15

Potassium chloride + bromine

Question 16

Pattern of reactivity up the group

Answer 16

More reactive elements at to and less reactive at bottom- opposite to group 1

Question 17

Why are these displacement reactions redox reactions

Answer 17

The ions of the less reactive metal gain electrons and are reduced.
The ions of the more reactive metal lose electrons and are oxidised

Question 18

Explain the relative reactivity of the halogens in terms of

electronic configurations

Answer 18

The larger the atom the less reactive, the force of attraction between the positively charges nucleus and a negatively charged electron from another atom becomes weaker therefore it becomes harder to gain outer electrons. Eg- chlorine is less reactive than fluorine because the outer shell of a chlorine atom is further away from the nucleus than the outer electrons in a fluorine atom.