Rutherfordium

Rutherfordium is element 104 and the first of the superheavy, or transactinide, elements. It does not exist in nature. Teams in Dubna (1964) and Berkeley (1969) each claimed it, the Soviets by firing neon nuclei at plutonium and the Americans by firing carbon at californium. After years of dispute, both share the credit, and the name honors Ernest Rutherford, who discovered the atomic nucleus.

It is made only a few atoms at a time. Most forms decay within seconds, though the longest-lived lasts on the order of an hour. Chemists have studied single atoms and found that it behaves like hafnium and zirconium, fitting its place in the periodic table.