2.8 explain the relative reactivities of the elements in Group 1 in terms of distance between the outer electrons and the nucleus

All elements in Group 1 have 1 electron in their outer shell. 

The elements further down the group are more reactive. This is because as you go down the group the outer shell (with the single electron) gets further away from the nucleus (as there are complete shells inbetween them). This means that, because the electron is further away, it is more easily lost (given away).

2.7 describe the relative reactivates of the elements in Group 1

Lithium reacts a little, however, as you get further down the group they react more. For example (reactions with water)...

Lithium - lithium moves slowly around the container, fizzing, until it disappears (approx. 30 seconds).

Sodium - sodium moves quickly around the container, fizzing rapidly, until it disappears (approx. 20 seconds). 

Potassium - potassium fizzes and reacts vigorously until it disappears (approx. 5 seconds)

2.6 describe the reactions of these elements with water ad understand that the reactions provide a basis or their recognition as a family of elements

Elements of the same family react in a similar way all. Group 1 elements (e.g. lithium, sodium, potassium) react in a similar way with water, because of this, we can class them as a family of elements.

Lithium, sodium and potassium all react vigorously with water. The reaction produces 2 products, 1 is a metal hydroxide, this solution is alkaline as, when a metal reacts with oxygen, an alkali solution is produced. The other product is hydrogen (which is why you can see effervescence). The word equation for the reaction of sodium (for example) and water is...

sodium + water ---> sodium hydroxide + hydrogen

2Na (s) + 2H2O(l) ---> 2NaOH(aq) + H2(g)