Group 7

Question 1

Explain why the reactivity of elements decreases as you go down Group 7

[3 marks]

Answer 1

As you go down, the number of energy levels increases, this means that the distance between the nucleus and the outershell electrons increases

This decreases the force of attraction between the negatively charged outer electrons and the positively charged nucleus

So the element gains electrons less easily

Question 2

Explain why hydrogen chloride is a gas at room temperature

Answer 2

Hydrogen chloride is a small molecule with

weak intermolecular forces

Which require only a little energy to overcome

( so hydrogen chloride has a low boiling point)