What is the atomic radius of chlorine?
There is no such thing as unified atomic radius. An atomic radius is a class consisting of van der Waals radii $R_\mathrm{vdW}$ (steric interactions), covalent radii $R_\mathrm{cov}$, and ionic radii $R_\mathrm{i}$ (and some other as well).

From the recent edition of CRC Handbook [1, p. 9-57]:


  $$
\begin{array}{llrr}
\hline
\text{Element} &amp; \text{Symbol} &amp; R_\mathrm{vdW}~(Å) &amp; R_\mathrm{cov}~(Å)\\
\hline
\text{Chlorine} &amp; \ce{Cl} &amp; 1.75 &amp; 1.00\\
\hline
\end{array}
$$


Ionic radii are given for the crystallographic data separately [1, p. 12-12]:


  $$
\begin{array}{llr}
\hline
\text{Ion} &amp; \text{C.N.} &amp; R_\mathrm{i}~(Å)\\
\hline
\ce{Cl^{+5}} &amp; 3~\text{(pyramidal)} &amp; 0.12\\
\ce{Cl^{+7}} &amp; 4 &amp; 0.08\\
\hline
\end{array}
$$


Reference


Haynes, W. M.; Lide, D. R.; Bruno, T. J. CRC handbook of chemistry and physics: a ready-reference book of chemical and physical data.; 2017; Vol. 97. ISBN 978-1-4987-5429-3.