Dubnium (Db)
Element 105 · transition metal · group 5, period 7
Dubnium is element 105, a transition metal in group 5 and period 7. Its electron configuration is [Rn] 5f14 6d3 7s2. The shells fill 2, 8, 18, 32, 32, 11, 2. Courses differ here. Counting only the outer s subshell gives 2; counting the inner d subshell with it gives 5, which is the group number. Its outer shell is already full, so it does not normally form ions at all.
- 105 protons
- 2/5 valence e−
- d-block
Properties
| Atomic number | 105 |
|---|---|
| Symbol | Db |
| Standard atomic weight | 268 u |
| Group | 5 |
| Period | 7 |
| Block | d-block |
| Category | transition metal |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d3 7s2 |
| Noble-gas notation | [Rn] 5f14 6d3 7s2 |
| Electrons per shell | 2, 8, 18, 32, 32, 11, 2 |
| Valence electrons | 2 or 5 |
| Common ionic charge | none |
| Electronegativity (Pauling) | no accepted value |
| Protons / electrons | 105 / 105 |
Electron configuration of dubnium
Orbitals fill from the lowest energy upward. Writing that out for dubnium gives 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d3 7s2, which is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d3 7s2 in plain text.
Everything up to Rn is the same as in that noble gas, so it is usually abbreviated to [Rn] 5f14 6d3 7s2. The part outside the bracket is what does the chemistry.
| Subshell | Electrons | Capacity |
|---|---|---|
| 1s | 2 | 2 |
| 2s | 2 | 2 |
| 2p | 6 | 6 |
| 3s | 2 | 2 |
| 3p | 6 | 6 |
| 3d | 10 | 10 |
| 4s | 2 | 2 |
| 4p | 6 | 6 |
| 4d | 10 | 10 |
| 4f | 14 | 14 |
| 5s | 2 | 2 |
| 5p | 6 | 6 |
| 5d | 10 | 10 |
| 5f | 14 | 14 |
| 6s | 2 | 2 |
| 6p | 6 | 6 |
| 6d | 3 | 10 |
| 7s | 2 | 2 |
Dubnium ion charge
Dubnium does not normally form ions. Its outer shell is already full, so there is nothing to gain by losing or gaining an electron.
Common questions
How many valence electrons does dubnium have?
There is no single agreed answer for dubnium. Courses differ here. Counting only the outer s subshell gives 2; counting the inner d subshell with it gives 5, which is the group number. Check which convention your course uses before answering.
What is the electron configuration of dubnium?
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d3 7s2, or [Rn] 5f14 6d3 7s2 written from the previous noble gas. Orbitals fill lowest energy first.
How many protons, electrons and neutrons does dubnium have?
A neutral dubnium atom has 105 protons and 105 electrons. Its standard atomic weight is 268, so the most common isotope has about 163 neutrons.
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