The biggest difference I can think of:
The Earth's interior is hot in part because of radioactive decay. It is hypothesized that our mantle convects (circulates) because of temperature differences within different regions of the Earth's interior. So if there were no radioactive material within the Earth, our interior temperature would be lower, mantle convection and tectonic plate movement would be greatly reduced as would volcanic activity. There might also be more homogenization of the interior.