This is
element 104, symbol
Rf, named after the
New-Zealand-born
Ernest Rutherford. A former
rival name for it was
kurchatovium, after the Soviet physicist
Igor Kurchatov, but rutherfordium is now the official name adopted by
IUPAC.
Atomic weight: about 264
An artificial element created in 1964 at the the Joint Nuclear Research Institute at Dubna in Russia, and subsequently reported also discovered at Berkeley in the USA in 1969: whence the rival names. Until the IUPAC decided to accept the name rutherfordium, it could also be provisionally called unnilquadium, symbol Unq.
It hasn't been created in macroscopic quantities, but would probably be a silvery metal chemically similar to hafnium.