Flerovium at a glance
- Atomic number
- 114
- Symbol
- Fl
- Atomic mass
- 289 u
- Category
- Post-transition metal
- Group / period
- 14 / 7
- Electron configuration
- [Rn] 5f 14 6d 10 7s 2 7p 2
- State at 25 °C
- Unknown
- Melting point
- n/a
- Boiling point
- n/a
- Density
- 9.9 g/cm³
- Electronegativity
- n/a
- 1st ionization energy
- 832 kJ/mol
- Oxidation states
- n/a
- Discovered
- 1998
Atomic structure
A neutral flerovium atom has 114 protons and 114 electrons, and its most common isotope carries about 175 neutrons. One atom weighs about 4.8 × 10⁻²⁵ kg, so a mole of flerovium (6.022 × 10²³ atoms) weighs 289 g. That nucleus holds 1.54 neutrons for every proton, typical of heavy nuclei, which need extra neutrons to hold together against the protons' repulsion. The electrons fill 7 shells (K 2, L 8, M 18, N 32, O 32, P 18, Q 4), which gives the configuration [Rn] 5f 14 6d 10 7s 2 7p 2. With 4 electrons in its outer shell, it usually shares electrons in covalent bonds. Every isotope is radioactive and short-lived; only a handful of atoms have ever been made, one at a time.
Physical properties
So little flerovium has ever existed at once that its melting point, boiling point and even its state at room temperature are unknown. Its density is 9.9 g/cm³ (predicted), 9.9 times as dense as water.
Chemical behaviour
It has no measured electronegativity. Pulling off its outermost electron takes 832 kJ/mol (predicted), more than Lead above it (716 kJ/mol). Group 14 also holds Carbon, Silicon, Germanium, Tin and Lead, which share its outer-shell pattern. Its Lewis symbol is Fl surrounded by 4 dots. Handle with care: as a pure element it is radioactive.
Where it comes from
It does not occur in nature in useful amounts; it is made in nuclear reactors or particle accelerators. It was first made at Dubna, with Lawrence Livermore by fusing plutonium-244 with calcium-48. Its longest-lived known isotope is Fl-289, about 2 seconds. It was first identified in 1998, making it the 113th element to be discovered (counting the 11 known since antiquity together).