I didn't think the Atkins book was that bad, personally. I did have a thermal physics background prior to using it, and there are better books out there (e.g., McQuarrie) but overall, I wouldn't call it "absolute trash." It doesn't give thorough derivations in spots but perhaps that's to be expected in a chemistry textbook. On a qualitative level at least, I found it to be more helpful than burdensome, that's for sure.
czelaya, you're talking about Physical Chemistry by Atkins and not Molecular Quantum Mechanics by the same author, correct? Either way, you don't need nearly the math background stated there. The necessary math to take (and understand) p-chem is single and multi-variable calculus with some exposure to very basic matrix algebra--taking PDEs, analysis, stat mech, etc. prior to Atkins is complete and utter overkill.