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). 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.