Using the data given in the table, deduce the state of each halogen at 20 ° C . Group 17 element Atomic radius / nm Melting point / ° C Boiling point / ° C Colour Fluorine ( F 2 ) 0 . 072 - 220 - 188 pale yellow Chlorine ( Cl 2 ) 0 . 099 - 101 - 35 green / yellow Bromine ( Br 2 ) 0 . 114 - 7 59 orange / brown Iodine ( I 2 ) 0 . 133 114 184 grey / black solid, purple vapour

The sub 0 ° C melting and boiling points of fluorine and chlorine mean that these two are gases at 20 ° C . A sub 0 ° C melting point and a boiling point greater than 20 ° C means that bromine is liquid at 20 ° C . High melting and boiling points of iodine mean that iodine is a solid at 20 ° C .

E M B I B E

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>BEFORE YOU START>Q 2

EASY

AS and A Level

IMPORTANT

Earn 100

The oxidation number of chlorine can vary. Give its oxidation number in $NaCl$ .

Important Questions on Group 17

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>BEFORE YOU START>Q 2

The oxidation number of chlorine can vary. Give its oxidation number in

NaClO

.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>BEFORE YOU START>Q 3

Explain which element is oxidised and which is reduced in this reaction:

$2 Fe (s) + 3 {Cl}_{2} (g) \to 2 {FeCl}_{3} (s)$

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>BEFORE YOU START>Q 4

Discuss with a partner what we mean by 'bond energy'.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>BEFORE YOU START>Q 4

State the unit that bond energies are expressed in.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>Question for discussion>Q •

Discuss with another learner or group of learners, do you believe that the uses of halogens and their compounds have had a positive or negative effect on the world, overall?

MEDIUM

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>Question>Q 1

Describe the trend in volatility you see going down Group 17.

MEDIUM

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 12 - Group 17>Question>Q 1

Using the data given in the table, deduce the state of each halogen at $20 ° C$ .

Group $17$ element	Atomic radius $/ nm$	Melting point $/ ° C$	Boiling point $/ ° C$	Colour
Fluorine ( $F_{2}$ )	$0.072$	$- 220$	$- 188$	pale yellow
Chlorine ( ${Cl}_{2}$ )	$0.099$	$- 101$	$- 35$	green / yellow
Bromine ( ${Br}_{2}$ )	$0.114$	$- 7$	$59$	orange / brown
Iodine ( $I_{2}$ )	$0.133$	$114$	$184$	grey / black solid, purple vapour