| Symbol | Pd |
| Atomic number | 46 |
| Group | 10 (Nickel group) |
| Period | 5 |
| Block | d |
| Classification | Transition Metal |
| Appearance | Silvery white |
| Color | Silver |
| Number of protons | 46 p+ |
| Number of neutrons | 60 n0 |
| Number of electrons | 46 e- |
| Phase at STP | Solid |
| Density | 12.023 g/cm3 |
| Atomic weight | 106.421 u |
| Melting point | 1828.05 K 1554.9 °C 2830.82 °F |
| Boiling point | 3236 K 2962.85 °C 5365.13 °F |
| Heat of vaporization | 393.3 kJ/mol |
| Electronegativity (Pauling Scale) | 2.2 |
| Electron affinity | 54.24 kJ/mol |
| Oxidation states | 0, +1, +2, +3, +4 (a mildly basic oxide) |
| Ionization energies |
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| Discovery and first isolation | William Hyde Wollaston (1802) |
Discovery of palladium William Hyde Wollaston noted the discovery of a new noble metal in July 1802 in his lab book and named it palladium in August of the same year. Wollaston purified a quantity of the material and offered it, without naming the discoverer, in a small shop in Soho in April 1803. After harsh criticism from Richard Chenevix, who claimed that palladium was an alloy of platinum and mercury, Wollaston anonymously offered a reward of £20 for 20 grains of synthetic palladium alloy. Chenevix received the Copley Medal in 1803 after he published his experiments on palladium. Wollaston published the discovery of rhodium in 1804 and mentions some of his work on palladium. He disclosed that he was the discoverer of palladium in a publication in 1805. It was named by Wollaston in 1802 after the asteroid 2 Pallas, which had been discovered two months earlier. | |