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Platinum

Element 78 · Transition metal

Specimen

Atomic number
78
Atomic mass
195.08
State at room temperature
Solid
Melting point
1,768 °C
Boiling point
3,825 °C
Density
21.46 g/cm³
Discovered
1735

Atomic mass from IUPAC.1 Other physical data from PubChem.2

Can I eat it?

In food and water
Not needed, little harm known. The body does not use platinum, and the RSC calls the metal non-toxic. The gut absorbs very little platinum. Some platinum salts cause allergy, and more exposure gives more risk. 34

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The atom

Pt
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) 32
5 (O) 17
6 (P) outermost 1
Total78

Configuration [Xe] 4f¹⁴ 5d⁹ 6s¹

4f ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓
5d ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑
6s ↑
A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 78 protons. The outermost shell is shown in red. Electrons do not travel on rings: they fill orbitals, regions where an electron is likely to be found. The boxes are those orbitals for the electrons outside the Xe core, with one arrow per electron.

Related elements

Group 10
Ni Nickel Pd Palladium Ds Darmstadtium

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Abridged Standard Atomic Weights 2024 .

    The atomic mass shown for the 84 elements that have a standard atomic weight.

  2. 2

    National Center for Biotechnology Information (PubChem), 2026. Periodic Table of Elements .

    Electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  3. 3

    Royal Society of Chemistry, Periodic Table, 2026. Platinum - Element information, properties and uses .

    Reference page; its Biological role and Natural abundance sections are quoted.

    • Platinum has no known biological role. It is non-toxic.
  4. 4

    World Health Organization, International Programme on Chemical Safety, 1991. Platinum (Environmental Health Criteria 125) , Section 1 summary, allergenicity.

    • Since only a minute amount of the 191 PtCl 4 given orally was absorbed
    • the risk of developing platinum salt sensitivity seems to be correlated with exposure intensity. Metallic platinum seems to be non-allergenic.
  5. 5

    National Institute of Standards and Technology (NIST), 2026. Atomic Weights and Isotopic Compositions for All Elements .

    Isotopic composition of each element; the most abundant isotope sets the neutron count in the nucleus view.