Prove that $\mathbb{Z} \times\Bbb Z_2$ and $\mathbb{Z}$ are not isomorphic.
Here by $\mathbb{Z}$ I mean the group $(\mathbb{Z},+)$ and by $\Bbb Z_2$ I mean the cyclic group of order 2.
This is exercise 2.3.13 part (a) from Dummit/Foote, Abstract Algebra - I am aware the solution may be posted somewhere online, but I try to look at full solutions as little as possible for my own understanding.
Here is my general argument. Is this a correct approach, and is it missing any important details?
Let $\Bbb Z_2=\{0,1\}$. The element $(0,1)$ in $\mathbb{Z} \times\Bbb Z_2$ has order 2, and since isomorphism preserves order of elements and there exists no integer with order 2, there cannot be an isomorphism between the groups.