Group 7 The Halogens

Question 1

What are elements found in group 7 called?

Answer 1

The Halogens

Question 2

List the first four elements of group 7 in order.

Answer 2

Fluorine, chlorine, bromine, iodine

Question 3

What is the colour and state of fluorine at room temperature?

Answer 3

Colour: pale yellow
State: gas

Question 4

What is the colour and state of chlorine at room temperature?

Answer 4

Colour: pale green
State: gas

Question 5

What is the colour and state of bromine at room temperature?

Answer 5

Colour: red-brown
Statement: liquid

Question 6

What is the colour and state of iodine at room temperature?

Answer 6

Colour: grey
State: solid

Question 7

What is a use for fluorine?

Answer 7

Dental products

Question 8

What is a use for chlorine?

Answer 8

Disinfect water in swimming pools

Question 9

What is a use for bromine?

Answer 9

Used in agriculture to stop fires

Question 10

What is a use for iodine?

Answer 10

Used in printing ink and dyes

Question 11

What are the formulae of the halogens?

Answer 11

Fluorine: F2
Chlorine: Cl2
Bromine: Br2
Iodine: I2

Question 12

When a halogen reacts with a metal a metal …….. is formed.

Answer 12

halide

Question 13

Describe observations when chlorine reacts with iron.

Answer 13

• pale green colour of chlorine changes into a brown red flame (iron chloride formed)
• quick reaction

Question 14

Describe observations when bromine reacts with iron.

Answer 14

• red-brown liquid (bromine) becomes an orange-brown solid (iron bromide)
• slow reaction -> requires more heat than chlorine and iron

Question 15

Describe observations when iodine reacts with iron.

Answer 15

• iodine starts as a grey solid and sublimes to a gas
• dull glow
• purple vapour is formed

Question 16

What is the word equation for chlorine reacting with iron? Include state symbols in your answer.

Answer 16

chlorine (g) + iron (s) -> iron chloride (s)

Question 17

What is the word equation for bromine reacting with iron? Include state symbols in your answer.

Answer 17

bromine (l) + iron (s) -> iron bromide (s)

Question 18

What is the word equation for iodine reacting with iron? Include state symbols in your answer.

Answer 18

iodine (s) + iron (s) -> iron iodide (s)

Question 19

What is the trend in reactivity of the halogens?

Answer 19

As you go down the group, the reactions become less vigorous (decrease in reactivity)