105[268]DbDubnium
Dubnium (Db) — element 105transition metal · group 5, period 7
Dubnium is a chemical element with the symbol Db and atomic number 105. It is a transition metal in group 5, period 7 of the periodic table (the d-block), with a standard atomic mass of [268] u. At room temperature (25 °C) dubnium is predicted to be of unknown state.
💡 Known for: Named after Dubna, Russia, home of the Joint Institute for Nuclear Research.
# Dubnium properties
| Symbol | Db |
|---|---|
| Atomic number | 105 |
| Atomic mass | [268] u |
| Category | transition metal |
| Group | 5 |
| Period | 7 |
| Block | d-block |
| Electron configuration | [Rn] 5f¹⁴ 6d³ 7s² |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d³ 7s² |
| Electrons per shell | 2, 8, 18, 32, 32, 11, 2 |
| Protons / electrons | 105 / 105 |
| State at 25 °C | unknown |
| Melting point | unknown |
| Boiling point | unknown |
| Density | 29.3 g/cm³ (predicted) |
| Electronegativity (Pauling) | — |
| First ionization energy | — |
| Atomic radius | — |
| Discovered | 1967 |
Values for superheavy elements are theoretical predictions; none have been measured in bulk.
# Electron configuration of dubnium
The electron configuration of dubnium is [Rn] 5f¹⁴ 6d³ 7s², written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d³ 7s². Its 105 electrons fill 7 shells as 2, 8, 18, 32, 32, 11, 2, so the outermost shell holds 2 electrons. Because only a few atoms have ever been made, this configuration is a theoretical prediction.
# Related elements
RfRutherfordiumprevious elementSgSeaborgiumnext elementVVanadiumgroup 5NbNiobiumgroup 5TaTantalumgroup 5ScScandiumtransition metalTiTitaniumtransition metalCrChromiumtransition metalMnManganesetransition metalFeIrontransition metalCoCobalttransition metalNiNickeltransition metalCuCoppertransition metal
# Dubnium FAQ
What is the atomic number of dubnium?
The atomic number of dubnium is 105: every dubnium atom has 105 protons in its nucleus. Its symbol is Db.
What is the atomic mass of dubnium?
The standard atomic mass of dubnium is [268] u (the mass number of its longest-lived isotope, since it has no stable isotopes).
What is the electron configuration of dubnium?
Dubnium's electron configuration is [Rn] 5f¹⁴ 6d³ 7s² (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d³ 7s²), with 2, 8, 18, 32, 32, 11, 2 electrons per shell.
Is dubnium a metal?
Yes. Dubnium is a transition metal, one of the metals.
What is the melting point of dubnium?
The melting point of dubnium is not known. These values are predictions.
What is dubnium used for / known for?
Named after Dubna, Russia, home of the Joint Institute for Nuclear Research.