Element 105
Dubnium (Db)
Dubnium (Db) is element 105 of the periodic table, a transition metal in period 7, group 5 (d-block) with an atomic mass of 268 and is a solid at standard conditions.
At a glance
- Atomic number
- 105
- Symbol
- Db
- Atomic mass
- 268 u
- Category
- Transition metals
- Period
- 7
- Group
- 5
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 5f14 6d3 7s2
- Shorthand configuration
- [Rn] 5f14 6d3 7s2
- Electrons per shell
- 2, 8, 18, 32, 32, 11, 2
- Oxidation states
- +5
Physical properties
- Density
- 29.3 g/cm3
- Phase
- solid
Atomic properties
- Covalent radius
- 149 pm
- First ionization energy
- 665 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Db-268 | 268.12567 | — | Half-life 16 hours |
Common uses
- Scientific research only
Discovery
- Year
- 1967
- Discovered by
- Joint Institute for Nuclear Research
- Country
- Russia