  We study the equation \begin{equation*}\label{P0} (-\Delta)^s u =
|x|^{\alpha} u^{\frac{N+2s+2\alpha}{N-2s}}\mbox{ in }\mathbb{R}^N,\tag{P}
\end{equation*} where $(-\Delta)^s$ is the fractional Laplacian operator with
$0 < s < 1$, $\alpha>-2s$ and $N>2s$. We prove the linear non-degeneracy of
positive radially symmetric solutions of the equation (\ref{P0}) and, as a
consequence, a uniqueness result of those solutions with Morse index equal to
one. In particular, the ground state solution is unique. Our non-degeneracy
result extends in the radial setting some known theorems done by D\'avila, Del
Pino and Sire (see \cite[Theorem 1.1]{Davila-DelPino-Sire}), and Gladiali,
Grossi and Neves (see \cite[Theorem 1.3]{Gladiali-Grossi-Neves}).
