You can install Atom very easily on Arch Linux, Atom is has a PKGBUILD on AUR.
We need Yaourt to install Atom, You can install Yaourt from here.
To install release built of Atom. Atom release downloads it from GitHub release builds.
yaourt -S atom-editor
To install Git built of Atom. Atom git builds Atom by downloading it from GitHub
yaourt -S atom-editor-git
Once Atom is done installing you can launch it from the application menu or execute.
By default Atom installs Atom's CLI tools in Linux.
The Atom release and the git built both will built Atom using Node.js on your system. Atom currently does not officially offer pre-built packages for any Linux distribution. Atom's performance will very depending on your system and may has longer load up time based on your system speed of opening applications. Atom has crossed build 100 which means Atom is more stable.
Now you have Atom installed on Arch Linux. If you have any problem feel free to leave a comment below.