Problem - Finite Abelian Group - Order of each element is = 2

Problem: G = {a1,a2,a3,..,an} is a finite abelian group where order of each element (except of identity of-course) is 2.

Prove

1. Order of G is of the form where k is a positive integer

2. a1.a2.a3....an = e (This is true for all values of n>2.)

My attempt for 1

If the group G, has a **proper** sub-group of order then it has a sub-group (may not be proper) of order . This is how I did it. Let H be a **proper** sub-group of order . Thus, b but b not . Consider where Hb is a coset of H. is a sub-group of order . Hence the result as there is a trivial sub-group of order 1 in G.

Any comments on this approach - is there a better way?

Any hints on 2?