1.5 Group 7: The Halogens

Question 1

What are the structure of halogens?

Answer 1

Small molecules made up of pairs of atoms

Question 2

Describe the pattern of the boiling and melting points going down the halogen group

Answer 2

Starts low and increases as you go down

Question 3

What colour and state is fluorine at room temp?

Answer 3

Pale yellow gas

Question 4

What colour and state is chlorine at room temp?

Answer 4

Green gas

Question 5

What colour and state is bromine at room temp?

Answer 5

Red-brown liquid

Question 6

What colour and state is iodine at room temp?

Answer 6

Grey solid

Question 7

What does iodine easily evaporate to form?

Answer 7

A violet gas

Question 8

Why do the halogens have low melting and boiling points?

Answer 8

They have small molecules made of pairs of atoms

Question 9

What charge do halide ions always have?

Answer 9

-1

Question 10

How can halogens bond with other elements?

Answer 10

• ionically with metals

* covalently with non metals

Question 11

What are formed when halogens bond covalently?

Answer 11

Molecules

Question 12

Describe the pattern of reactivity as you go down the halogen group

Answer 12

It decreases going down the group

Question 13

What can a more reactive halogen do to a less reactive halogen from an aqueous solution of a halide compound?

Answer 13

The more reactive halogen can displace the less reactive halogen

Question 14

How could you show that chlorine is more reactive than bromine?

Answer 14

Add choline solution to a solution of a metal bromide and bromine will be displaced by chlorine

Question 15

Why does the reactivity decrease as you go down the halogens?

Answer 15

The attraction between the outer electrons and the nucleus decreases as the number of occupied shells increases

Question 16

What type of element are the halogens?

Answer 16

Non metals

Question 17

What is shielding?

Answer 17

When the number of shells increases making it harder for another electron to be attracted because it is less reactive

Question 18

Why does the reactivity of a halogen depend on the attraction between the nucleus and the electrons?

Answer 18

The protons in the nucleus attract the electrons so if other electrons are shielding the nucleus then it is less reactive

Question 19

Why does the density of a halogen increase going down the group?

Answer 19

Because of the high increase in mass and the small increase in volume as you go down the table