I have a lenovo g500 laptop which currently runs with windows 10?

It has 2gb ram, 2.40gz processor (intel i3).
Is it compatible with os x. Any mac os.

In order to run Mac OS on a PC you need run something called Hackintosh. And getting OS X to run on a PC is not easy, you'd have to really want to do it badly.

If you don't like windows you can always go Linux!