Americium,   ₉₅ Am

Spectral lines of americium
????? ????
Pronunciation	/ ? æ m ? ? r ? s i ? m / AM -?- RIS -ee-?m
Appearance	silvery white
Americium ?? ?????? ???? ??
Eu ↑ Am ↓ (Uqe) plutonium ← americium → curium ‍
????? ????? ( Z )	95
???? , ??????	group n/a , period 7
????	f-block
Element category	actinide
Mass number	243 (most stable isotope)
Electron configuration	[ Rn ] 5f 7 7s 2
Electrons per shell	2, 8, 18, 32, 25, 8, 2
????? ????
???? (at  STP )	????
????? ???? ???	1449  K ​(1176 °C, ​2149 °F)
???? ???	2880 K ​(2607 °C, ​4725 °F) (calculated)
Density near  r.t.	12 g/cm 3
Heat of fusion	14.39  kJ/mol
Molar heat capacity	62.7 J/(mol·K)
Vapor pressure P   (Pa) 1 10 100 1 k 10 k 100 k at  T   (K) 1239 1356
????? ????
Oxidation states	8, 7, 6, 5, 4, 3 , 2 ​(an amphoteric oxide)
Electronegativity	Pauling scale: 1.3
Ionization energies	1st: 578 kJ/mol
Atomic radius	empirical: 173  pm
Covalent radius	180±6 pm
Miscellanea
Crystal structure	​ double hexagonal close-packed (dhcp)
? ?????? ???????	10 W/(m·K)
Electrical resistivity	0.69 μΩ·m [?]
Magnetic ordering	paramagnetic
Magnetic susceptibility ( χ mol )	+1000.0·10 ?6  cm 3 /mol [?]
CAS Number	7440-35-9
History
Naming	after the Americas
Discovery	Glenn T. Seaborg , Ralph A. James , Leon O. Morgan , Albert Ghiorso (1944)
Main isotopes of americium
????­??? Abun­dance ??? ???? ( t 1/2 ) Decay mode Pro­duct ?????:Infobox element/isotopes decay2 ?????:Infobox element/isotopes decay3 ?????:Infobox element/isotopes decay2
view   ?   talk   ?   edit | references | in Wikidata

????????? (?? ??????? : Americium ) ?? ??????? ?????? ??? ?? ?? ?? ?? ?????? ???? ?? ? Am ????? ?? ?? ???? ????? ?? ????? ???? ??? ??.

?????? [ ???? ]

??????? [ ???? ]

?????? [ ???? ]

? ??????? ?????? [ ???? ]

?????? [ ???? ]

1. ↑ Muller, W.; Schenkel, R.; Schmidt, H. E.; Spirlet, J. C.; McElroy, D. L.; Hall, R. O. A.; Mortimer, M. J. (1978). "The electrical resistivity and specific heat of americium metal". Journal of Low Temperature Physics . 30 (5?6): 561. Bibcode : 1978JLTP...30..561M . doi : 10.1007/BF00116197 . ?????? |CitationClass= ?? ???? ?????? ??? ( ?????? )
2. ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics . Boca Raton, Florida: Chemical Rubber Company Publishing. ????? E110. ? ???? ??????? ??? ?????   0-8493-0464-4 . ?????? |CitationClass= ?? ???? ?????? ??? ( ?????? )