Answer
$2 ; \lt -1,0 \gt$
Work Step by Step
As we know that the unit vector $\hat{\textbf{u}}$ is defined as: $\hat{\textbf{u}}=\dfrac{v}{|v|}$
Now, we have: $|v|=\sqrt{(-2)^2+(0)^2}=\sqrt {4}=2$
Thus, $\hat{\textbf{u}}=\dfrac{v}{|v|}=\dfrac{\lt -2,0 \gt}{2}= \lt -1,0 \gt$
