Rutherfordium

At a glance

Symbol

Rf

Atomic number

104

Mass number of its longest-lived isotope

[267]

Group

4

Period

7

Family

transition metal

Electron configuration

[Rn] 5f¹⁴ 6d² 7s² (predicted)

Electronegativity

not measured

Common ions

predicted +4, like hafnium

On the table

Period 7, group 4. The other transition metals are tinted, and every cell opens its own article.

Electrons and bonding

Only a handful of atoms have ever been made, each lasting seconds or less, so its chemistry is predicted from its place in the table rather than measured.

Properties

State at 25 °C

not known

Physical properties

none measured; no more than a few atoms have ever existed at once

Where it is found

Not found in nature. It is made a few atoms at a time in particle accelerators by fusing lighter nuclei, and each atom decays within seconds to hours.

Discovery and name

A team at Dubna in the Soviet Union led by Georgy Flerov reported it in 1964 and proposed kurchatovium; Albert Ghiorso's team at Berkeley reported it in 1969 and proposed rutherfordium. The rival claims for elements 104 to 106, known as the Transfermium Wars, were settled in 1997, when IUPAC chose rutherfordium, after the physicist who discovered the atomic nucleus.