Group 7

Question 1

What block are group 7 elements classed as and why

Answer 1

P block elements, because their highest energy electron is in a p sub shell.

Question 2

Give the colours and state of each group 7 element

Answer 2

Question 3

What type of bonds form between atoms in group 7 molecules

Answer 3

Covalent bonds

Question 4

What type of bonds form between molecules of group 7 elements

Answer 4

Induced dipole dipole forces

Question 5

What type of structure do group 7 elements form

Answer 5

Simple covalent structure

Question 6

Are group 7 molecules polar or non polar

Answer 6

Non polar

Question 7

How does the strength of the induced dipole dipole forces between molecules differ

Answer 7

The more electrons in the molecules, the stronger the induced dipole dipole forces between them

Question 8

How does boiling point of group 7 molecules change as you descend the group and why?

Answer 8

The boiling point increases as you go down the group, as the number of electrons increases- this causes the induced dipole dipole forces between the molecules to get stronger and require more energy to break. To boil the molecules, only these forces must be broken

Question 9

What is the name of group 7 elements

Answer 9

Halogens

Question 10

What is a halide ion

Answer 10

An ion of a group 7 element

Question 11

Do halogens act as oxidising agents or reducing agents? Why?

Answer 11

They act as oxidising agents.
This is because oxidising agents get reduced themselves by taking electrons from other elements, and halogens take 1 electron from other elements.

Question 12

What is the most powerful oxidising agent in group 7 and why

Answer 12

Fluorine, because it attracts electrons more easily due to the shielding being weak and atomic radius being small, causing the nuclear force to be stronger

Question 13

Explain how reactivity changes as you descend group 7

Answer 13

Reactivity decreases as you descend group 7 because the outer electrons get further from the nucleus (the atomic radius increases), and shielding increases. This causes the outer shell to experience less nuclear attraction so it’s harder to attract an electron

Question 14

Give 1 way the decrease in reactivity as you descend group 7 has been shown

Answer 14

Displacement reactions between the group 7 elements

Question 15

Define a displacement reaction with halogens

Answer 15

A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of its halide ions.

Question 16

Draw the table that shows the different colours of the displacement of Chlorine, Bromine and Iodine when either dissolved in water or an organic solvent

Answer 16

Question 17

When chlorine is bubbled through an aqueous solution of potassium iodide, the solution becomes brown due to the formation of iodine. Write the ionic equation for this.

Answer 17

Question 18

How do you know what elements to include in an ionic equation

Answer 18

Only include things that have changed oxidation state, as they have gained or lost electrons

Question 19

When Bromine is added to a solution of Potassium Iodide, the solution becomes brown due to the formation of Iodine. Write the ionic equation for this.

Answer 19

Question 20

Draw the displacement summary table (include what would happen in the reaction between Cl, Br and I molecules and ions, and what colour would be formed in both water and organic solvents

Answer 20

Question 21

Draw the displacement summary table (include what would happen in the reaction between Cl, Br and I molecules and ions, and what colour would be formed in both water and organic solvents

Answer 21

Black shaded box= no reaction

Question 22

Define a disproportionation reaction

Answer 22

A reaction in which the same element is both oxidised and reduced

Question 23

What happens when chlorine is reacted with aqueous sodium hydroxide

Answer 23

It disproportionates to form a solution containing chlorate and chloride ions

Question 24

What is the formula for the chlorate ion present in bleach

Answer 24

Question 25

Write the equation for the reaction of Chlorine in cold, dilute sodium hydroxide.

Answer 25

Question 26

Give the equation for when Chlorine reacts with water. Is this a disproportionation reaction and why?

Answer 26

Yes this is a disproportionation reaction, as Cl was reduced from 0 to -1 in HCl and oxidised from 0 to +1 in HOCl

Question 27

Give an advantage and disadvantage of adding chlorine to drinking water

Answer 27

Advantage - the chlorine destroys bacteria and makes water safer to drink Disadvantage- chlorine is toxic, and it can react with organic compounds in water to form chlorinated hydrocarbons which can cause cancer

Question 28

Iodide ions react with Chlorate (I) ions and water to form iodine, chloride ions and hydroxide ions. Write a balanced equation for this reaction.

Answer 28

Question 29

Give 2 steps you should carry out to test for the presence of halide ions in an aqueous solution

Answer 29

Add silver nitrate solution Add dilute or concentrated ammonia solution (depending on the result from the silver nitrate solution)

Question 30

Draw the table that shows the results from adding Silver nitrate and Ammonia to Chlorine solution, Bromine solution and Iodine solution.

Answer 30

Question 31

Write the ionic equation, including state symbols, for the reaction between chloride ions and silver nitrate

Answer 31

Question 32

Write the ionic equation, including state symbols, for the reaction between Bromide ions and silver nitrate

Answer 32