EDIT : This issue is already fixed in the latest atom releases.
atom on a terminal will show you why:
/usr/share/atom/atom: error while loading shared libraries: libXss.so.1: cannot open shared object file: No such file or directory
This solution for this is simple. Just install the following package:
sudo dnf install libXScrnSaver
Seems that the RPM is missing this dependency. The bug is already reported here.