Topic 6

Question 1

chlorine at room temp

Answer 1

fairly reactive, poisonous, green gas

Question 2

bromine at room temp

Answer 2

poisonous, red-brown liquid

Question 3

iodine at room temp

Answer 3

dark grey crystalline solid which gives off orange vapour when heated

Question 4

describe the chemical test for chlorine

Answer 4

hold piece of damp blue litmus paper over gas. Chlorine will bleach litmus paper, turning it white. It may also turn red for a moment first because a solution of chlorine is acidic

Question 5

describe the alkali meals

Answer 5

• soft

- have relatively low melting points

Question 6

describe the reaction of lithium with water

Answer 6

lithium will move around surface, fizzing furious

Question 7

describe the reaction of sodium and potassium with water

Answer 7

move around surface, fizzing furiously and also melt in heat of reaction. potassium even gets hot enough to ignite hydrogen gas being produced

Question 8

describe the pattern of reactivity of the alkali metals (group 1)

Answer 8

elements get more reactive as you go down group because outer electron is more easily lost as further from nucleus so less strongly attracted to nucleus, less energy needed to remove it

Question 9

describe the pattern in physical properties of the halogens (group 7)

Answer 9

as go down group, melting and boiling points increase

Question 10

Halogen reacting with metals

Answer 10

react vigorously with metals to form salts called’metal halides’. Halogens higher up in group 7 more reactive because can attract an outer electron of metal more easily

Question 11

halogens reacting with hydrogen

Answer 11

form hydrogen halides. hydrogen halides are soluble and can dissolve in water to form acidic solutions

Question 12

using displacement reactions what can you predict about reactions of astatine

Answer 12

since astatine is east reactive halogen you’d predict it wouldn’t displace any other halogens from their salt solution

Question 13

explain why halogen displacement reactions are redox reactions

Answer 13

halogens gain electrons whilst halide ions lose electrons

Question 14

describe the reactivity of halogens

Answer 14

as go down halogens become less reative- it gets harder to attract extra electron to fill outer shell when further away from nucleus

Question 15

explain why group 0 elements are chemically inert

Answer 15

they have full outer shell of electrons, means don’t easily give up or gain electrons

Question 16

describe the use of the noble gas argon

Answer 16

provides inert atmosphere in filament lamps since it’s non-flammable, it stops very hot filament from burning away

Question 17

describe the use of the noble gas helium

Answer 17

use in airships and balloons. helium has lower density than air so makes balloons float, also non-flammable makes it safer than hydrogen gas

Question 18

describe pattern in physical properties of group 0 (noble gases)

Answer 18

boiling point, melting point and density increase as go down group