Answer
$\text{Amplitude}= 1$
$\text{Period}= 4\pi$
Work Step by Step
Recall:
For $y=A\sin{(ωx)}$, we have:
$\text{Amplitude}=|A|\quad \quad \text{and} \quad \quad \text{Period}=T=\frac{2\pi}{ω}$
In $y=-\sin {\left(\frac{1}{2}x\right)}$, we have $A=-1$ and $\omega=\frac{1}{2}$ so
$\text{Amplitude}= |A|=1$
$\text{Period}=T=\dfrac{2\pi}{\omega}=\dfrac{2\pi}{\frac{1}{2}}=4\pi$
