Group 1

Question 1

Trend: why does the density increase down the group?

Answer 1

There are more electron shells therefore, the atoms get bigger resulting in them piling more space (more dense).

Question 2

Trend: why does the reactivity increase down the group?

Answer 2

The outer electron is further from the positive nucleus, meaning there is a weaker attraction and that the outermost electron is in most easily lost.

Question 3

Trend: why does the melting point decrease down the group?

Answer 3

There are more electron shells, meaning delocalised electrons are further from the nucleus, resulting in a weaker attraction.