Palladium can be used to make electronic and dental appliances, and can be alloyed with ruthenium, iridium, silver, gold, copper, etc., to improve palladium's resistivity, hardness, and strength, and is used to make precision resistors.
The second major application of palladium in electronics is in capacitors, where palladium and palladium-silver alloys are used as electrodes. Palladium (or palladium-nickel alloys) can be used as connectors, accessory components or soldering materials in consumer electronics. In 2006, Johnson Matthey reported that the electronics industry used 1.07 million troy ounces (33.2 tons) of palladium that year.
Palladium belongs to the tenth group of elements in the periodic table, but his outermost electron configuration obeys the Hund's rule. Electrons in the s-shell layer migrate to fill the lower-energy d-orbitals.
Palladium is a soft silver-white metal similar to platinum, and has the lowest density and melting point of the platinum group of metals. It is soft and ductile when annealed, and improves strength and hardness when cold worked. Platinum can be slowly dissolved in concentrated nitric acid, hot concentrated sulfuric acid and room temperature aqua regia, and can be dissolved in hydrochloric acid after fine grinding.
Palladium does not react with oxygen at standard temperatures and therefore does not lose its luster in air. Palladium heated to 800°C will produce a layer of palladium oxide and will discolor slightly in humid air containing sulfur.
Bombarding a palladium film with alpha particles at a low temperature of 3.2 K will produce defects that exhibit superconductivity.
Isotopes
Naturally occurring palladium has seven different isotopes, six of which are stable.
The most stable radioactive isotopes are 107 palladium with a half-life of 6.5 million years (which can be found in nature), 103 palladium with a half-life of 17 days, and 100 palladium with a half-life of 3.63 days.
An additional 18 radioactive isotopes of palladium have been found, 91 palladium through 123 palladium, with their atomic weights ranging from 90.94948(64) amu (91 palladium) to 122.93426(64) amu (123 palladium).
All 18 isotopes have half-lives of less than 30 minutes, except for 101 palladium (half-life of 8.47 hours), 109 palladium (half-life of 13.7 hours), and ?112 palladium (half-life of 21 hours).