Dubnium (Db)
Transition metal · d-block · period 7 · group 5
Known only as a handful of atoms.
Dubnium (symbol Db) is chemical element number 105, a transition metal in group 5, period 7 of the periodic table. Its standard atomic weight is (268) and its electron configuration is [Rn] 5f14 6d3 7s2. Its state at room temperature is unknown, and it is radioactive. Named after Dubna, the Russian research town where many heavy elements were made.
Properties
| Atomic number | 105 |
|---|---|
| Atomic mass | (268) |
| Category | Transition metal |
| Block | d-block |
| Group · Period | 5 · 7 |
| Electron configuration | [Rn] 5f14 6d3 7s2 |
| Electrons per shell | 2, 8, 18, 32, 32, 11, 2 |
| State at 25 °C | unknown |
| Melting point | — |
| Boiling point | — |
| Density | — |
| Electronegativity (Pauling) | — |
| Radioactive | Yes — no stable isotope |
| Origin | synthetic |
| Discovered | 1970 · Dubna / Berkeley |
Key facts about Dubnium
- Named after Dubna, the Russian research town where many heavy elements were made.
- Settled a long naming dispute between Soviet and American teams.
- Behaves chemically like tantalum and niobium.
- Most stable isotope lasts about a day.
What Dubnium is used for
None — research only.
Where it sits in the periodic table
Dubnium is in group 5, period 7, of the d-block. Its electron configuration [Rn] 5f14 6d3 7s2 means its outermost shell holds 2 electrons, which is what places it here and explains much of its chemistry. See Dubnium on the interactive table →
Dubnium — frequently asked questions
What is Dubnium used for?
None — research only.
Is Dubnium radioactive?
Yes. Dubnium has no stable isotope, so every form of it is radioactive.
What is the electron configuration of Dubnium?
Dubnium has the electron configuration [Rn] 5f14 6d3 7s2, which is 2, 8, 18, 32, 32, 11, 2 electrons per shell.
What group and period is Dubnium in?
Dubnium is in group 5, period 7, in the d-block. Its outer shell holds 2 electrons.
Who discovered Dubnium?
Dubnium was discovered in 1970 by Dubna / Berkeley.