Element 78 · Transition metal
Platinum (Pt) — Element 78
Spanish platina — little silver
Platinum (Pt) is a transition metal in Period 6, Group 10 of the periodic table with atomic number 78, standard atomic weight 195.08 u, and ground-state electron configuration [Xe] 4f¹⁴ 5d⁹ 6s¹. At standard temperature and pressure it is classified as a solid with 10 valence electrons and common oxidation states +2, +4.
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What are the atomic properties and physical constants of Platinum?
Reference constants compiled from IUPAC standard atomic weights, the NIST Atomic Spectra Database, and the CRC Handbook.
- Atomic number (Z)
- 78
- Standard atomic mass
- 195.08 u
- Chemical family
- Transition metal
- Ground-state configuration
- [Xe] 4f¹⁴ 5d⁹ 6s¹
- Electrons per shell
- 2, 8, 18, 32, 17, 1
- Valence electrons
- 10
- Common ion charges / oxidation states
- +2, +4
- Phase at STP
- Solid
- Pauling electronegativity
- 2.28 Pauling
- First ionization energy
- 870 kJ/mol
- Atomic radius
- 177 pm
- Melting point
- 1,768 °C
- Boiling point
- 3,825 °C
- Discovery year
- 1735
- Table coordinate
- Period 6, Group 10
- Radioactivity
- Has stable isotope(s)
How are electrons arranged across Platinum’s shells?
A neutral Platinum atom contains 78 electrons distributed across 6 occupied principal energy shells ([Xe] 4f¹⁴ 5d⁹ 6s¹). The table below compares Platinum’s shell occupancy against each shell’s theoretical 2n² capacity.
| Principal Shell (n) | Spectroscopic Letter | Electrons in Pt | Max Shell Capacity (2n²) |
|---|---|---|---|
| n = 1 | K | 2 e⁻ | 2 e⁻ |
| n = 2 | L | 8 e⁻ | 8 e⁻ |
| n = 3 | M | 18 e⁻ | 18 e⁻ |
| n = 4 | N | 32 e⁻ | 32 e⁻ |
| n = 5 | O | 17 e⁻ | 50 e⁻ |
| n = 6 | P | 1 e⁻ | 72 e⁻ |
Frequently Asked Questions about Platinum (Pt)
What is the atomic mass and atomic number of Platinum (Pt)?
Platinum (Pt) has atomic number Z = 78 (78 protons in its nucleus) and an IUPAC standard atomic weight of 195.08 u. It sits in Period 6, Group 10 and is classified as a transition metal.
What is the ground-state electron configuration of Platinum?
The neutral ground-state electron configuration of Platinum (Z = 78) is [Xe] 4f¹⁴ 5d⁹ 6s¹. Across its 6 occupied principal shells (n = 1 to n = 6), the electrons per shell are 2, 8, 18, 32, 17, 1, with 10 valence electrons participating in bonding.
What are the common ion charges and electronegativity of Platinum?
Platinum commonly forms +2, +4 oxidation states or ion charges in compounds. Its Pauling electronegativity is 2.28 and its first ionization energy is 870 kJ/mol.
When was Platinum discovered and what is it used for?
Platinum was discovered in 1735 (Spanish platina — little silver). Catalytic converters, jewelry, labs
How does Platinum compare to neighboring elements?
Other transition metal elements: