PTL:Palladium
From ChemEd Collaborative
Palladium is a transition metal in Group VIIIB (Group 10) in the 5th period. Other members of the group are nickel (Ni) and platinum (Pt).
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Discovered
Palladium was discovered in 1803 by Wollaston and
Name
named for the asteroid Pallas, which was discovered at about the same time.
Characteristics
Palladium is steel-white, has the lowest melting point, and is the least dense of the platinum group metals. Its electrical conductivity is similar to that of Pt. (Both Pd and Pt have much lower electrical conductivities than the elements that follow, Ag and Au, respectively.)
Found
The metal is found along with the other platinum-group metals (Ru, Os, Ir, Rh, Pd, and Pt) in deposits in the Soviet Union and South Africa, among other places.
Palladium is steel-white, has the lowest melting point, and is the least dense of the platinum group metals. Its electrical conductivity is similar to that of Pt. (Both Pd and Pt have much lower electrical conductivities than the elements that follow, Ag and Au, respectively.)
Reactions
Unlike platinum, Pd is attacked by nitric and sulfuric acids. The metal does not tarnish in air.
Uses
At room temperature the metal has the property of absorbing up to 900 times its volume of H2 gas, presumably by placing H atoms in the interstices among the metal atoms. Thus, H2 gas can diffuse through Pd metal. Since this is the only gas capable of this, the phenomenon provides a method for purifying H2.
Finely divided palladium is a good catalyst for hydrogenation and dehydrogenation reactions. Palladium is used in jewelry to make white gold, an alloy with gold, and the metal is used in making [electrical contacts].
Emission Spectra
This is the emission spectra for Palladium.
