Caption

Copernicium (Cn). Diagram of the nuclear composition and electron configuration of an atom of copernicium-285 (atomic number: 112), the most stable isotope of this radioactive element. The nucleus consists of 112 protons (red) and 173 neutrons (blue). 112 electrons (green) bind to the nucleus, successively occupying available electron shells (rings). Copernicium, named after Nicolaus Copernicus and first synthesised in 1996, is a transactinide and transition metal in group 12, period 7, and the d-block of the periodic table. Copernicium-285 has two forms (nuclear isomers), with half-lives of 29 seconds and 8.9 minutes.