Group 7

Question 1

Group 7 elements

Answer 1

Fluorine
Chlorine
Bromine
Iodine

Question 2

What state is fluorine at room temperature?

Answer 2

Gas

Question 3

What colour is fluorine gas?

Answer 3

Pale yellow

Question 4

Does fluorine dissolve in water?

Answer 4

No

Question 5

Does fluorine dissolve in organic solvents eg hexane?

Answer 5

No

Question 6

What state is chlorine at room temperature?

Answer 6

Gas

Question 7

What colour is chlorine gas?

Answer 7

Green

Question 8

Does chlorine dissolve in water?

Answer 8

Yes

Question 9

What colour is chlorine dissolved in water?

Answer 9

Pale green to colourless

Question 10

What colour is chlorine dissolved in hexane?

Answer 10

Virtually colourless

Question 11

What state is bromine in at room temperature?

Answer 11

Liquid

Question 12

Bromine liquid colour

Answer 12

Red-brown

Question 13

Does bromine dissolve in water?

Answer 13

Yes

Question 14

Bromine water colour

Answer 14

Yellow-orange

Question 15

Does bromine dissolve in hexane?

Answer 15

Yes

Question 16

Bromine dissolved in hexane colour

Answer 16

Orange-red

Question 17

What state is iodine in at room temperature?

Answer 17

Solid

Question 18

Iodine solid colour

Answer 18

Grey

Question 19

Does iodine dissolve in water

Answer 19

Barely

Question 20

What colour does iodine dissolved in water form?

Answer 20

A brown solution

Question 21

Can iodine dissolve in iodine compound solvents (such as KI)?

Answer 21

Yes and forms a brown solution

Question 22

What colour does iodine dissolved in ethanol form?

Answer 22

Yellow

Question 23

What colour does iodine dissolved in hexane form?

Answer 23

Purple

Question 24

Iodine gas colour

Answer 24

Purple

Question 25

How does the reactivity of halogens change down the group?

Answer 25

Decreases

Question 26

Why does the reactivity of halogens decrease down the group?

Answer 26

Because they react by gaining an electron to complete outer shell
Going down the group, the atomic radii increases so:
Outer electrons experience more shielding due to more internal electrons
Outer shell electrons are further from nucleus
So decreased electrostatic attraction between nucleus and reacting electron due to experiencing less nuclear force
(Overcomes increase in number of protons)

Question 27

How does electro negativity of halogens change down the group?

Answer 27

Decreases down the group

Question 28

Why does electronegativity of halogens decrease down the group?

Answer 28

Because electronegativity is ability to attract bonding pair of electrons to nucleus
Going down the group the atomic radii increases so the number of electrons shielding bonded pair of electrons from nuclear charge increases and bonding pair of electrons is at a further distance from nucleus
This decreases nuclear force thus EN decreases down the group
(Overcomes increasing proton number)

Question 29

How does melting and boiling point change down the group?

Answer 29

Increases down the group

Question 30

Why does the mp/bp increase down the group?

Answer 30

Because going down group 7, there is an increase in atomic radii thus more electrons per atom
So an increase in number of London forces formed between diatomic molecules
Therefore, more energy is needed to overcome these London forces to melt or boil

Question 31

Why do halogens not react as easily with water?

Answer 31

Because water is a polar solvent that can form London forces, permanent dipole dipole forces AND hydrogen bonds
Halogen molecules are non polar thus do not dissolve as readily

Question 32

Why do halogens dissolve easily with organic solvents eg hexane?

Answer 32

Because they are both non polar

Question 33

Why is the ionic radii of halide ions larger than the atomic radii of its respective element?

Answer 33

Because halide ions have one more electron
Which increases repulsion
Which expands radii