Have all the naturally occurring elements been discovered?

In a word, yes. The heaviest naturally occurring element is #92, uranium. The elements beyond that have nuclei that just don't hold together for long enough to be found in natural environments. read more

All the elements that naturally occur under conditions found near the surface of the Earth have probably been discovered. Most heavy elements now being discovered are being created through particle physics, and only exist for short times before decaying. read more

All the natural elements from 1, Hydrogen, to 92, Uranium, have been discovered. In the case of element number 2, Helium, it was actually discovered in the Sun before being found on Earth. Of these elements only element number 43, Technetium, (and possibly element 61, Promethium) was man-made before its discovery. read more