Group 7 Elements

Question 1

what are halogens?

Answer 1

group 7 elements - that are covalently bonded, simple molecular substances

Question 2

what properties do halogens have?

Answer 2

• all are diatomic
• colours get darker down the group
• MP/BP increases down the group

Question 3

what is the formula of fluorine?

Answer 3

F2

Question 4

what is the formula of chlorine?

Answer 4

Cl2

Question 5

what is the formula of bromine?

Answer 5

Br2

Question 6

what is the formula of iodine?

Answer 6

I2

Question 7

what is the formula of astatine?

Answer 7

At2

Question 8

what is the colour of fluorine?

Answer 8

very pale yellow

Question 9

what is the colour of chlorine?

Answer 9

pale green

Question 10

what is the colour of bromine?

Answer 10

brown

Question 11

what is the colour of iodine?

Answer 11

dark grey

Question 12

what is the colour of astatine?

Answer 12

black

Question 13

what state is fluorine?

Answer 13

gas

Question 14

what state is chlorine?

Answer 14

gas

Question 15

what state is bromine?

Answer 15

liquid

Question 16

what state is iodine?

Answer 16

solid

Question 17

what state is astatine?

Answer 17

solid

Question 18

what other features does bromine have?

Answer 18

volatile, releases brown fumes

Question 19

what other features does iodine have?

Answer 19

sublimes, releases purple fumes

Question 20

what happens when halogens react with metals?

Answer 20

they form ionic compounds

Question 21

what happens in a halogen-metal reaction?

Answer 21

the outer shell electrons from the metal are transferred to the halogen

Question 22

what type of reaction is a halogen-metal reaction?

Answer 22

a redox reaction

Question 23

why is a halogen-metal reaction a redox reaction?

Answer 23

• Na loses electrons = oxidised
• Cl gains electrons = reduced
• Cl also changes its name from chlorine atom -> chloride ion
• Halogen -> halide

Question 24

what happens as halogens go down the group?

Answer 24

they get less reactive

Question 25

how do halogen atoms fill their outer shell?

Answer 25

they need to gain an electron

Question 26

why does halogen atoms becoming halide ions happen less easily as you go down the group?

Answer 26

• atoms have more electron shells
• the extra electron is further from the nucleus
• so its attraction to the nucleus is weaker

Question 27

what happens when the electrons move closer and further away from the nucleus?

Answer 27

• close to the nucleus = strong attraction
• far from the nucleus = weak attraction

Question 28

what is the chemical test for chlorine?

Answer 28

• damp blue litmus paper turns white
• this is because the chlorine act as a bleaching agent, so it removes the colour from the paper