#78 / 118
78Pt195.08
Transition Metalssolid at STPD-block

Platinum

Group: 10Period: 6Standard Atomic Weight: 195.08 u

Why is Platinum in this position?

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

Group Assignment
Group 10

Belongs to Group 10 because it has 10 valence electrons (5d⁹ 6s¹).

Period Assignment
Period 6

Belongs to Period 6 because its outermost electron occupies n=6.

Orbital Block
D-block

Belongs to the d-block because its differentiating electrons occupy 5d orbitals.

Chemical Category
Transition Metals

Classified as a transition metal and precious noble platinum group metal.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 18, 32, 17, 1]

Bohr Atomic Shell Model(2, 8, 18, 32, 17, 1)

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

78 Protons (p⁺)117 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 17Shell O: Electron 2 of 17Shell O: Electron 3 of 17Shell O: Electron 4 of 17Shell O: Electron 5 of 17Shell O: Electron 6 of 17Shell O: Electron 7 of 17Shell O: Electron 8 of 17Shell O: Electron 9 of 17Shell O: Electron 10 of 17Shell O: Electron 11 of 17Shell O: Electron 12 of 17Shell O: Electron 13 of 17Shell O: Electron 14 of 17Shell O: Electron 15 of 17Shell O: Electron 16 of 17Shell O: Electron 17 of 17PShell P: Electron 1 of 1PtZ = 78

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):17 / 50 electrons (34%)
Shell P (n=6):1 / 72 electrons (1%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁹ 6s¹

Neutral ground state configuration. Valence electrons: 10.

Atomic & Quantum Properties

Electronegativity (Pauling)2.28 Pauling
1st Ionization Energy870 kJ/mol
Electron Affinity-205.3 kJ/mol
Atomic Radius (empirical)177 pm
Common Oxidation States+2, +4
Crystal StructureFCC

Physical & Thermal Properties

Density at STP21.45 g/cm³
Melting Point1768.3 °C (2041.4 K)
Boiling Point3825 °C (4098 K)
Magnetic OrderingParamagnetic
Discovery Year1735
Discovered ByAntonio de Ulloa

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Automotive catalytic converters eliminating toxic carbon monoxide and hydrocarbons
  • Cisplatin, carboplatin, and oxaliplatin anti-cancer chemotherapy drugs
  • Proton-exchange membrane (PEM) fuel cells powering hydrogen vehicles
  • Fine jewelry, bridal wedding rings, and investment bullion
Occurrence in Nature

Mined from the Bushveld Igneous Complex in South Africa, the Norilsk deposit in Russia, and Sudbury basin in Canada.

Etymology & Name Origin

From Spanish 'platina' meaning little silver

Important Chemical Compounds
PtO₂ (Adams' catalyst)
cis-[Pt(NH₃)₂Cl₂] (Cisplatin)
H₂PtCl₆ (Chloroplatinic acid)
Interesting Chemical Facts
  • Platinum features an electron configuration anomaly ([Xe] 4f¹⁴ 5d⁹ 6s¹) due to relativistic stabilization of d-orbitals.
  • Cisplatin, a simple platinum coordination complex discovered in 1965, cures over 90% of testicular cancer cases by cross-linking cancer cell DNA.
  • All the platinum ever mined in human history would fit inside a small cube measuring less than 8 meters on each side.
Safety & Handling Note

Metallic platinum is completely non-toxic and hypoallergenic; soluble platinum salts (chloroplatinates) are potent respiratory allergens.