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

Physical data from PubChem.¹

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. ²³

The atom

Shell	Electrons
1 (K)	2
2 (L)	8
3 (M)	18
4 (N)	32
5 (O)	17
6 (P) outermost	1
Total	78

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

Sources

1

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

Atomic mass, electron configuration, melting and boiling points, density and discovery year for all 118 elements.
2
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.
3
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.

Specimen

Can I eat it?

The atom

Related elements

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Sources