The symbols in my .tex documents are not the same as in other formats

I’m really new using atom, and I’m trying to use as my .tex editor, but I could not write some symbols, as " \ " when I type it, it prints " ’ ’ " instead.
It only happens in the .tex documents, so I’m not sure what could be the problem.

I’m using manjaro cinnamon, and atom 1.5.0.