78 - Platinum transition metal
Discovered by Antonio de Ulloa in 1735
Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, gray-white transition metal. Its name is derived from the Spanish term platina, which is literally translated into "little silver".
Periodic table
| Shell | Electrons | Orbitals |
|---|---|---|
| 1 | 2 | 2 in 1s |
| 2 | 8 | 2 in 2s + 6 in 2p |
| 3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
| 4 | 32 | 2 in 4s + 6 in 4p + 10 in 4d + 14 in 4f |
| 5 | 17 | 2 in 5s + 6 in 5p + 9 in 5d |
| 6 | 1 | 1 in 6s |
Electron shells
silvery white Appearance
195 u Atomic Mass
1.35 Å Atomic Radius
4.1k K Boiling Point
10 Group
2, 4 Common Oxidation States
1.36 Å Covalent Radius
21.4 g/cm³ Density
205 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s1 4f14 5d9 Electron Configuration
[Xe] 4f14 5d9 6s1 Electron Configuration (semantic)
2.28 Electronegativity
78 Electrons
8.96 eV First Ionization Energy
870, 1791 kJ/mol Ionization Energies
2.05k K Melting Point
68 Mendeleev Number
25.9 J/(mol·K) Molar Heat
6 Number of Shells
117 Neutrons
78 Atomic Number
32 Number of Isotopes
-2, 2, 4, 5, 6 Oxidation States
6 Period
Solid Phase
78 Protons
2, 8, 18, 32, 17, 1 Electron Shell Occupations
0.133 J/(g K) Specific Heat