Copernicium

At a glance

Symbol

Cn

Atomic number

112

Mass number of its longest-lived isotope

[285]

Group

12

Period

7

Family

transition metal

Electron configuration

[Rn] 5f¹⁴ 6d¹⁰ 7s² (predicted)

Electronegativity

not measured

On the table

Period 7, group 12. 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

Sigurd Hofmann's team at GSI made it in 1996 by fusing zinc and lead nuclei. The name, after the astronomer Nicolaus Copernicus, was announced in 2010 on February 19, his birthday.