#105 / 118
105Db[268]
Superheavy / Unknownsolid at STPD-block

Dubnium

Group: 5•Period: 7•Standard Atomic Weight: [268] u
Open Full Periodic TableView Bohr Model

Why is Dubnium in this position?

Understanding the scientific rationale behind Dubnium's position in the periodic table:

Group Assignment
Group 5

Belongs to Group 5 as the 6d homologue of Vanadium, Niobium, and Tantalum (6d³ 7s²).

Period Assignment
Period 7

Belongs to Period 7 because its outermost electrons occupy n=7.

Orbital Block
D-block

Belongs to the d-block because valence electrons fill 6d orbitals.

Chemical Category
Superheavy / Unknown

Classified as a superheavy transition metal.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 18, 32, 32, 11, 2]

Bohr Atomic Shell Model(2, 8, 18, 32, 32, 11, 2)

Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.

105 Protons (p⁺)163 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 8Shell L: Electron 2 of 8Shell L: Electron 3 of 8Shell L: Electron 4 of 8Shell L: Electron 5 of 8Shell L: Electron 6 of 8Shell L: Electron 7 of 8Shell L: Electron 8 of 8MShell M: Electron 1 of 18Shell M: Electron 2 of 18Shell M: Electron 3 of 18Shell M: Electron 4 of 18Shell M: Electron 5 of 18Shell M: Electron 6 of 18Shell M: Electron 7 of 18Shell M: Electron 8 of 18Shell M: Electron 9 of 18Shell M: Electron 10 of 18Shell M: Electron 11 of 18Shell M: Electron 12 of 18Shell M: Electron 13 of 18Shell M: Electron 14 of 18Shell M: Electron 15 of 18Shell M: Electron 16 of 18Shell M: Electron 17 of 18Shell M: Electron 18 of 18NShell N: Electron 1 of 32Shell N: Electron 2 of 32Shell N: Electron 3 of 32Shell N: Electron 4 of 32Shell N: Electron 5 of 32Shell N: Electron 6 of 32Shell N: Electron 7 of 32Shell N: Electron 8 of 32Shell N: Electron 9 of 32Shell N: Electron 10 of 32Shell N: Electron 11 of 32Shell N: Electron 12 of 32Shell N: Electron 13 of 32Shell N: Electron 14 of 32Shell N: Electron 15 of 32Shell N: Electron 16 of 32Shell N: Electron 17 of 32Shell N: Electron 18 of 32Shell N: Electron 19 of 32Shell N: Electron 20 of 32Shell N: Electron 21 of 32Shell N: Electron 22 of 32Shell N: Electron 23 of 32Shell N: Electron 24 of 32Shell N: Electron 25 of 32Shell N: Electron 26 of 32Shell N: Electron 27 of 32Shell N: Electron 28 of 32Shell N: Electron 29 of 32Shell N: Electron 30 of 32Shell N: Electron 31 of 32Shell N: Electron 32 of 32OShell O: Electron 1 of 32Shell O: Electron 2 of 32Shell O: Electron 3 of 32Shell O: Electron 4 of 32Shell O: Electron 5 of 32Shell O: Electron 6 of 32Shell O: Electron 7 of 32Shell O: Electron 8 of 32Shell O: Electron 9 of 32Shell O: Electron 10 of 32Shell O: Electron 11 of 32Shell O: Electron 12 of 32Shell O: Electron 13 of 32Shell O: Electron 14 of 32Shell O: Electron 15 of 32Shell O: Electron 16 of 32Shell O: Electron 17 of 32Shell O: Electron 18 of 32Shell O: Electron 19 of 32Shell O: Electron 20 of 32Shell O: Electron 21 of 32Shell O: Electron 22 of 32Shell O: Electron 23 of 32Shell O: Electron 24 of 32Shell O: Electron 25 of 32Shell O: Electron 26 of 32Shell O: Electron 27 of 32Shell O: Electron 28 of 32Shell O: Electron 29 of 32Shell O: Electron 30 of 32Shell O: Electron 31 of 32Shell O: Electron 32 of 32PShell P: Electron 1 of 11Shell P: Electron 2 of 11Shell P: Electron 3 of 11Shell P: Electron 4 of 11Shell P: Electron 5 of 11Shell P: Electron 6 of 11Shell P: Electron 7 of 11Shell P: Electron 8 of 11Shell P: Electron 9 of 11Shell P: Electron 10 of 11Shell P: Electron 11 of 11QShell Q: Electron 1 of 2Shell Q: Electron 2 of 2DbZ = 105

Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.

Electron Shell Filling Breakdown

Shell K (n=1):2 / 2 electrons (100%)
Shell L (n=2):8 / 8 electrons (100%)
Shell M (n=3):18 / 18 electrons (100%)
Shell N (n=4):32 / 32 electrons (100%)
Shell O (n=5):32 / 50 electrons (64%)
Shell P (n=6):11 / 72 electrons (15%)
Shell Q (n=7):2 / 98 electrons (2%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f¹⁴ 6s² 6p⁶ 6d³ 7s²

Neutral ground state configuration. Valence electrons: 5.

Atomic & Quantum Properties

Electronegativity (Pauling)Not available
1st Ionization Energy665 kJ/mol
Electron AffinityNot available
Atomic Radius (empirical)149 pm
Common Oxidation States+5
Crystal StructureBCC (predicted)

Physical & Thermal Properties

Density at STP29.3 g/cm³ (predicted)
Melting Point2200 °C (2473 K)
Boiling Point5600 °C (5873 K)
Magnetic OrderingParamagnetic
Discovery Year1968
Discovered ByJoint Institute for Nuclear Research (Dubna) & Lawrence Berkeley Lab

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Fundamental nuclear physics and superheavy chemical bond research
Occurrence in Nature

Synthesized in accelerators by bombarding Californium-249 with Nitrogen-15 or Americium-243 with Neon-22.

Etymology & Name Origin

Named after the science town of Dubna in Russia, home to the Joint Institute for Nuclear Research (JINR)

Important Chemical Compounds
DbCl₅ (Dubnium pentachloride)
DbBr₅ (Dubnium pentabromide)
Interesting Chemical Facts
  • • Dubnium was named in 1997 honoring the Russian research town of Dubna, where six superheavy elements have been discovered.
  • • Gas-phase chromatography experiments revealed that Dubnium pentachloride (DbCl₅) adsorbs to surfaces more like niobium than tantalum due to relativistic charge distributions.
  • • Dubnium-268 has an unusually long half-life of 28 hours, decaying predominantly by spontaneous fission.
Safety & Handling Note

Intensely radioactive; experimental quantities are limited to isolated atoms.

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