Unit 2 Group 7

Question 1

What is the trend in boiling points for group 7

Answer 1

The boiling points increase as you go down the group as each atom gains an extra outer shell of electrons so it will for more van der walls forces between molecules, so requires more energy to break bonds.

Question 2

What is the trend in electro-negativity for group 7

Answer 2

The electro-negativity decreases down group 7, this is because the outer electrons are further away from the nucleus due to increased shielding so they have a weaker attraction to the nucleus

Question 3

What is the colour of the solution formed when Chlorine water reacts with KBr

Answer 3

Orange solution of Br2 is formed

Question 4

What is the colour of the solution formed when Chlorine water is reacted with KI

Answer 4

A brown solution forms of I2

Question 5

What is the colour of the solution formed when Bromine water reacts with KI

Answer 5

A brown solution of I2 forms

Question 6

Why is Chlorine added to water

Answer 6

Chlorine kills bacteria and micro-organisms in the water making it safe to drink