Seaborgium (Sg)
Element 106 · Transition metal · atomic mass [269] u · group 6, period 7
Electron shells: 2, 8, 18, 32, 32, 12, 2
Seaborgium was the first element named directly after a living person, which was controversial at the time. Its chemistry has been shown to resemble tungsten, as the table predicts.
Glenn Seaborg could receive post addressed purely in chemical symbols: Sg, Lr, Bk, Cf, Am.
- Atomic number
- 106
- Atomic mass
- [269] u
- Electron configuration
- [Rn] 7s² 5f¹⁴ 6d⁴
- Group · period · block
- 6 · 7 · d
- Oxidation states
- 0, +3, +4, +5, +6
- Electronegativity
- Not measured
- Melting point
- —
- Boiling point
- —
- Density
- Not measured
- State at 20 °C
- Unknown
- Appearance
- Unknown; presumed metallic
- Discovered
- Albert Ghiorso and colleagues, 1974
106 protons, and 106 electrons when neutral
Mass number of the longest-lived isotope — no standard atomic weight exists
Chromium group
What Seaborgium is used for
- Scientific research only
Atomic structure of Seaborgium
A neutral seaborgium atom has 106 protons and 106 electrons. Its most common isotope carries about 163 neutrons, which is where the mass number 269 comes from. Change the neutron count and you have a different isotope of seaborgium; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8, 18, 32, 32, 12, 2. In orbital notation that is [Rn] 7s² 5f¹⁴ 6d⁴. As a d-block element its valence count is variable, which is why it can form compounds in several oxidation states.
3D electron orbitals
See where Seaborgium's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Seaborgium sits in the periodic table
Discovery and naming
Seaborgium was discovered by Albert Ghiorso and colleagues in 1974. Its name comes from Glenn T. Seaborg, which is also why its symbol (Sg) does not match its English name.
Every isotope of seaborgium is radioactive, so it has no standard atomic weight. Periodic tables show the mass number of its longest-lived isotope in square brackets instead.
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Seaborgium?
Seaborgium has no stable isotope, so it has no standard atomic weight. Periodic tables instead show 269 in square brackets — the mass number of its longest-lived isotope.
How many protons, neutrons and electrons does Seaborgium have?
Seaborgium has 106 protons, because the atomic number is the proton count and that is what makes an atom Seaborgium at all. A neutral Seaborgium atom has the same number of electrons, 106. The neutron count varies by isotope; the most common one has about 163, since 269 − 106 = 163.
What is the electron configuration of Seaborgium?
The electron configuration of Seaborgium is [Rn] 7s² 5f¹⁴ 6d⁴. Its electrons are arranged 2, 8, 18, 32, 32, 12, 2 across 7 shells.
Is Seaborgium a metal?
Yes. Seaborgium is classified as a transition metal, on the metallic side of the table.
What group and period is Seaborgium in?
Seaborgium is in group 6 (the chromium group), period 7, in the d-block. The group is its column and the period is its row.
What is the charge of Seaborgium?
Seaborgium most commonly forms a 6+ ion. Like most transition metals it has several accessible oxidation states, so the charge depends on the compound. Across all its compounds it shows oxidation states of 0, +3, +4, +5, +6.
What is Seaborgium used for?
Scientific research only. Seaborgium was the first element named directly after a living person, which was controversial at the time.
Who discovered Seaborgium, and where does its name come from?
Seaborgium (Sg) was discovered by Albert Ghiorso and colleagues in 1974. The name comes from Glenn T. Seaborg.
Is Seaborgium radioactive?
Yes. Every isotope of Seaborgium is radioactive — it has no stable form at all, which is why the periodic table shows its mass in square brackets rather than as a standard atomic weight.