This is because uranium is man made.
Plutonium is an artificial element; natural plutonium exist only in extremely traces.
Yes, plutonium is an artificial element, man made.
Plutonium is a radioactive chemical element; practically all plutonium is man made - in the nature plutonium is extremely rare.
Some plutonium chemical compounds; plutonium dioxide, plutonium nitride, plutonium carbide, plutonium nitrate, plutonium trifluoride, plutonium chloride, etc.
Some isotopes of cesium are radioactive and synthetic, as indicated in recent news reports about the Japanese nuclear reactor damaged by the recent severe earthquake/tsunami. (The radioactive cesium reported was formed by atomic fission of uranium and/or plutonium in the reactor.) However, most cesium is neither radioactive nor synthetic!
Pretty much all elements after Uranium are synthetic (made by man) Any element above 94 (plutonium and neptunium were also discovered in extremely small concentrations in uranium minerals), are all considered synthetic since they do not occur naturally on the earth, but were made under laboratory conditions.
Examples are: plutonium metal, isotope Pu-238, plutonium dioxide, plutonium sulfide, plutonium nitrate, plutonium carbide etc.
Examples: PuO2, plutonium nitrate, plutonium carbide, plutonium chloride, plutonium fluoride etc.
Plutonium chemical properties:- plutonium is a reactive metal: the Pauling electronegativity is 1,28- plutonium is flammable- plutonium has six allotropes- plutonium in compounds has valences from 2 to 7- plutonium is very toxic
There's no plutonium here. I haven't even seen any plutonium, recently.
Pure plutonium contain only plutonium atoms.
Plutonium is only paramagnetic.