With polar coordinates this can also be done :)
\draw (\a:1) circle (0.2cm);
The syntax is (<angle>:<radius>)
. The output is

% arara: pdflatex
% !arara: indent: {overwrite: yes}
\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\foreach \a in {0, 30, ..., 350 }
\draw (\a:1) circle (0.2cm);
\end{tikzpicture}
\end{document}
Or, alternatively, using the graphs
library, allows you to use
\graph[nodes={draw,circle,minimum width=.2cm},
clockwise,
radius=1cm,
empty nodes,
n=12]{subgraph I_n};
here's a complete MWE:
% arara: pdflatex
% !arara: indent: {overwrite: yes}
\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{graphs}
\usetikzlibrary{graphs.standard}
\begin{document}
\begin{tikzpicture}
\graph[nodes={draw,circle,minimum width=.2cm},clockwise,radius=1cm,empty nodes,n=12]{subgraph I_n};
\end{tikzpicture}
\end{document}
For reference, see Where can I find a complete list of the standard subgraphs offered by tikz?
(10:2)
which is(<angle>:radius)