#44 / 118
44Ru101.07
Transition Metalssolid at STPD-block

Ruthenium

Group: 8Period: 5Standard Atomic Weight: 101.07 u

Why is Ruthenium in this position?

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

Group Assignment
Group 8

Belongs to Group 8 because it has 8 valence electrons (4d⁷ 5s¹).

Period Assignment
Period 5

Belongs to Period 5 because its outermost electron occupies n=5.

Orbital Block
D-block

Belongs to the d-block because its differentiating electrons occupy the 4d subshell.

Chemical Category
Transition Metals

Classified as a transition metal and a member of the noble platinum group metals.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 18, 15, 1]

Bohr Atomic Shell Model(2, 8, 18, 15, 1)

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

44 Protons (p⁺)57 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 15Shell N: Electron 2 of 15Shell N: Electron 3 of 15Shell N: Electron 4 of 15Shell N: Electron 5 of 15Shell N: Electron 6 of 15Shell N: Electron 7 of 15Shell N: Electron 8 of 15Shell N: Electron 9 of 15Shell N: Electron 10 of 15Shell N: Electron 11 of 15Shell N: Electron 12 of 15Shell N: Electron 13 of 15Shell N: Electron 14 of 15Shell N: Electron 15 of 15OShell O: Electron 1 of 1RuZ = 44

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):15 / 32 electrons (47%)
Shell O (n=5):1 / 50 electrons (2%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁷ 5s¹

Neutral ground state configuration. Valence electrons: 8.

Atomic & Quantum Properties

Electronegativity (Pauling)2.2 Pauling
1st Ionization Energy710.2 kJ/mol
Electron Affinity-101.3 kJ/mol
Atomic Radius (empirical)178 pm
Common Oxidation States+3, +4
Crystal StructureHCP

Physical & Thermal Properties

Density at STP12.45 g/cm³
Melting Point2334 °C (2607 K)
Boiling Point4150 °C (4423 K)
Magnetic OrderingParamagnetic
Discovery Year1844
Discovered ByKarl Ernst Claus

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Wear-resistant electrical contacts and thick-film chip resistors
  • Grubbs' catalysts for olefin metathesis in organic polymer synthesis (2005 Nobel Prize)
  • Chlor-alkali electrolytic cell titanium anode coatings (RuO₂ / Dimensionally Stable Anodes)
  • Solar dye-sensitized solar cells (Graetzel cells)
Occurrence in Nature

Occurs as native platinum group metal alloy nuggets and in nickel-copper sulfide ore refining residues.

Etymology & Name Origin

From Latin 'Ruthenia', the historical Latin name for Russia

Important Chemical Compounds
RuO₄ (Ruthenium tetroxide)
RuCl₃ (Ruthenium trichloride)
Grubbs catalyst
Interesting Chemical Facts
  • Ruthenium can achieve a maximum oxidation state of +8 in Ruthenium tetroxide (RuO₄), a volatile yellow toxic solid.
  • The 2005 Nobel Prize in Chemistry was awarded to Chauvin, Grubbs, and Schrock for developing ruthenium catalysts that reorganize organic double bonds.
  • Adding just 0.1% ruthenium to titanium increases its corrosion resistance to boiling hydrochloric acid by over a hundredfold.
Safety & Handling Note

Ruthenium tetroxide (RuO₄) is a volatile, potent oxidizer and biological tissue irritant; bulk metal is chemically inert.