A mixed number is simply a whole number and a fraction written together.
The mixed numbers between 1 and 2 on the number line can be any range of fractions written along with 1 as the whole. It cannot include the number 2, because if that happens, then the number has crossed beyond 2 on the number line.
An example of a mixed number that comes between 1 and 2 on the number line is
[tex]1\frac{3}{4}[/tex]