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Sm
62
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63
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64
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94
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95
Cm
96
 
 
 

 

Periodic table

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Americium

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Americium

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Américium

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Americij

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Americio

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Americio

 

Am
Am
Americium

PERIODIC TABLE OF THE ELEMENTS

AMERICIUM

TRANSITION ELEMENT:
ACTINIDE

 

Atomic number:95

Group numbers:3

Period:7

Electronic configuration:[Rn] 5f7 7s2

Formal oxidation number:+3 +4 +5 +6

Electronegativities:-

Atomic radius / pm:173

Relative atomic mass:[243]

 

Americium was discovered by Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, and Albert Ghiorso (US) in 1944. Named for the American continent. It is a silvery-white, artificially produced radioactive metal. Americium was produced by bombarding plutonium with neutrons. Americium-241 is currently used in smoke detectors.

PHYSICAL PROPERTIES

Density / g dm-3:13670 (293 K)

Molar volume / cm3mol-1:17.78 (293 K)

Electrical resistivity / μΩcm:68 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:10

Melting point / °C:1176

Boiling point / °C:2011

Heat of fusion / kJ mol-1:14.4

Heat of vaporization / kJ mol-1:238.5

Heat of atomization / kJ mol-1:266

IONIZATION ENERGIES

First ionization energy / kJ mol-1:576.39

Second ionization energy / kJ mol-1:-

Third ionization energy / kJ mol-1:-

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:-

in the oceans / ppm:-

CRYSTALLOGRAPHIC DATA

hexagonal

Crystal structure:

hexagonal

Unit-cell dimensions / pm:

a=346.80, c=1124.0

Space group:

P63/mmc

ISOTOPES

IsotopeRelative atomic massMass percent (%)

REDUCTION POTENTIALS

Balanced half-reaction Eo / V

 

94 Plutonium <=
95 Americium
=> 96 Curium