Page 21 - Curriculum Visions Dynamic Book

Americium (Am)
Element 95. It is an artificial, radioactive rare earth in the actinide series in the Periodic Table.
It is also called a transuranium element because it has a higher atomic number than uranium. It is made from plutonium in a nuclear reactor.
Key facts...
Name: americium
Symbol: Am
Atomic number: 95
Atomic weight: 243
Position in Periodic Table: inner transition
metal; period 7 (actinide series)
State at room temperature: solid
Colour: silvery-white
Density of solid: 13.7 g/cc
Melting point: 994°C
Boiling point: 2,600°C
Origin of name: it was named after America. Shell pattern of electrons: 2–8–18–32–25–8–2
The metal is silvery-white. It is not very reactive and tarnishes only slowly in air. It is about three times as radioactive as radium.
Geology
It is not present in rocks because it does not occur naturally.
Biology
Americium is radioactive and so can theoretically be dangerous to health. However, because it is not highly radioactive, it is safe to use in the tiny quantities needed for smoke detection.
Americium radioactive source
Discovery
It was discovered in the United States by Glenn Seaborg, Ralph James, L. Morgan and Albert Ghiorso in 1944 during experiments in a nuclear reactor.
Technology
Americium is the radioactive source in smoke detectors. It is also used where portable gamma rays are needed for scientific purposes.
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