Roughly, the early Macintoshes were all built on Motorola's 68000 series chips -- 680020 to, I think 680040 if memory serves (leedle joke there).

These models includes the original Classic, the SE, and the Mac II series which include the II, the II Cx, and II fx.

Right around there they shifted to the Power PC chip family, and I believe (I could be wrong) that the early Performas and the 8100 and later were all power PC based. A variety of PPC machines were produced over the last four years, and then a major step up occurred with the advent of the G3 PPC in 1998 and the G4 PPC in 1999.

That's a short version. More details can be found at apple.com, or by doing a web search on Macintosh history -- I would do it for you but I am running late at the moment...