Unknown propertiesElement 114 · p-block

Flerovium (Fl)

Flerovium (Fl), element 114, is a synthetic superheavy element whose chemical properties have not been measured; its most stable known isotope has mass number 290. Only a few atoms have ever been made, so its bulk properties are predictions.

114FlFlerovium[290]

Atomic number

114

protons

Atomic weight

[290]

most stable isotope

Melting point

—

Boiling point

—

Density

9.928 g/cm³

predicted

Electronegativity

—

Pauling scale

State at 25 °C

Unknown

Discovered

1998–1999

Russia (Dubna)

Flerovium at a glance

Identity

Symbol	Fl
Atomic number (Z)	114
Atomic weight	[290] mass number of the most stable isotope
Category	Unknown properties
Group	14 — carbon group
Period	7
Block	p-block
CAS number	54085-16-4

Atomic properties

Electron configuration	[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p² Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d¹⁰ 7s² 7p²
Electrons per shell	2, 8, 18, 32, 32, 18, 4
Covalent radius	143 pm

Physical properties

State at 25 °C	Unknown
Density	9.928 g/cm³ (predicted)

Isotopes & abundance

Natural occurrence	Synthetic
Radioactive	Yes
Most stable isotope	²⁹⁰Fl — half-life 80 s
Known isotopes	8

Atomic weights: CIAAW Abridged Standard Atomic Weights 2024. Other properties: standard reference compilations, checked October 2026; predicted values are marked.

Flerovium electron configuration

Flerovium has 114 electrons. Written in short form, its ground-state configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p² — the electrons of the noble gas radon, plus 5f¹⁴ 6d¹⁰ 7s² 7p².Written out in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d¹⁰ 7s² 7p².

As a member of group 14 it has 4 valence electrons in its outer shell (shell 7), which largely decide its chemistry.

5f↑↓↑↓↑↓↑↓↑↓↑↓↑↓

6d↑↓↑↓↑↓↑↓↑↓

7s↑↓

7p↑↑

Discovery and name

Discovered

1998–1999 — Joint Institute for Nuclear Research with Lawrence Livermore National Laboratory · Russia (Dubna).

Name

The Flerov Laboratory of Nuclear Reactions (after Georgy Flerov).

Known for

Predicted to sit near an 'island of stability'; experiments suggest a relatively inert, volatile metal.

Isotopes of flerovium

Flerovium has no stable isotopes and does not occur naturally in significant amounts. Its longest-lived known isotope is:

Isotope	Protons	Neutrons	Half-life
²⁹⁰Fl	114	176	80 s

8 isotopes of flerovium are known in our data set (half-lives as published in nuclear data tables).

Flerovium compared with group 14

The other elements in group 14 (carbon group), from top to bottom of the table:

Element	Z	Atomic weight	Melting point	Boiling point	Density	Electronegativity
Carbon	6	12.011	—	3,642 °C	2.2 g/cm³	2.55
Silicon	14	28.085	1,414 °C	3,265 °C	2.33 g/cm³	1.9
Germanium	32	72.630	938 °C	2,833 °C	5.323 g/cm³	2.01
Tin	50	118.71	232 °C	2,586 °C	7.287 g/cm³	1.96
Lead	82	207.2	327 °C	1,749 °C	11.3 g/cm³	2.33
Flerovium	114	[290]	—	—	9.928 g/cm³ (pred.)	—

Frequently asked questions

4 answers

What is the atomic mass of flerovium?

Flerovium has no stable isotopes, so it has no standard atomic weight. Periodic tables show [290], the mass number of its most stable known isotope.

How many protons, neutrons and electrons does flerovium have?

A neutral flerovium atom has 114 protons and 114 electrons. Its most stable isotope, flerovium-290, has 176 neutrons.

What is the electron configuration of flerovium?

[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p² (in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d¹⁰ 7s² 7p²).

Who discovered flerovium?

1998–1999 — Joint Institute for Nuclear Research with Lawrence Livermore National Laboratory (Russia (Dubna)).