Americium

Americium (Am)

Americium is the 95th element in the periodic table and has a symbol of Am and atomic number of 95. It has an atomic weight of (243) and a mass number of 223. Americium has ninety-five protons and one hundred twenty-eight neutrons in its nucleus, and ninety-five electrons in seven shells. It is located in group Actinides, period seven and block f of the periodic table. Radioactive metallic transuranic element, belongs to the actinoids. Ten known isotopes. Am-243 is the most stable isotope, with a half-life of 7.95*10^3 years. Discovered by Glenn T. Seaborg and associates in 1945, it was obtained by bombarding Uranium-238 with alpha particles.
Atomic Number95
Atomic Weight243
Mass Number223
Group
Period7
Blockf
Protons95 p+
Neutrons128 n0
Electrons95 e-
Animated Bohr Model of Am (Americium)

Physical Properties

Atomic Radius
Molar Volume
Covalent Radius
Metallic Radius
Ionic Radius
Crystal Radius
Van der Waals Radius
Density
Atomic Radii of the Elements: Americium0102030405060708090100110120130140150160170180190200210220230240250pmAtomic RadiusCovalent RadiusMetallic RadiusVan der Waals Radius

Chemical Properties

Energy
Proton Affinity
Electron Affinity
Ionization Energy
Ionization Energies of Am (Americium)
Heat of Vaporization
Heat of Fusion
Heat of Formation
Electrons
Electron Shells2, 8, 18, 32, 25, 8, 2
Bohr Model: Am (Americium)
Valence Electrons2
Lewis Structure: Am (Americium)
Electron Configuration[Rn] 5f7 7s2
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 5f7 7s2
Enhanced Bohr Model of Am (Americium)
Orbital Diagram of Am (Americium)
Oxidation States2, 3, 4, 5, 6, 7
Electronegativity
Electrophilicity Index
States of Matter
PhaseSolid
Gas Phase
Boiling Point
Melting Point
Critical Pressure
Critical Temperature
Triple Point
Visual

Americium is a Silver. Am has a CPK of #ffffff, Jmol of #545cf2, and MOLCAS GV of #545cf2. The Appearance of Element 95 is silvery white.

Color
Silver
Appearancesilvery white
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
Molar Heat Capacity
Specific Heat Capacity
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
Type
Electrical Conductivity
Electrical Resistivity
Superconducting Point
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.0000000515 m³/Kg
Magnetic Susceptibility (Molar)
0.00000001251 m³/mol
Magnetic Susceptibility (Volume)
0.000704
Magnetic Ordering
Curie Point
Neel Point
Structure

The lattice angles of Americium are π/2, π/2, 2 π/3.

Crystal StructureSimple Hexagonal ()
Lattice Constant
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young's Modulus
Poisson Ratio
Speed of Sound
Classification

The Glawe Number of Americium is 39. The Mendeleev Number of Am is 26. The Pettifor Number of Element 95 is 42. The Goldschmidt Class of Americium (Am) is synthetic.

CategoryActinides, Actinides
CAS Group
IUPAC Group
Glawe Number39
Mendeleev Number26
Pettifor Number42
Geochemical Class
Goldschmidt Classsynthetic

Other

The Dipole Polarizability of Americium is 131 plus or minus 25 a₀. The Allotropes of Am is . The Neutron Cross Section of Element 95 is 74. The Quantum Numbers of Americium (Am) is 8S7/2. The Space Group of Americium is 194 (P63/mmc).

Gas Basicity
Dipole Polarizability
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
74
Neutron Mass Absorption
Quantum Numbers8S7/2
Space Group194 (P63/mmc)

Isotopes of Americium

Stable Isotopes0
Unstable Isotopes27
Natural Isotopes0

223Am

Mass Number223
Neutron Number128
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
10 ± 9 ms
Spin9/2
Quadrupole Moment
Discovery Year2015
Parity-

Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)

224Am

Mass Number224
Neutron Number129
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin
Quadrupole Moment
Discovery Year
Parity

Decay ModeIntensity
α (α emission)
SF (spontaneous fission)

225Am

Mass Number225
Neutron Number130
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin9/2
Quadrupole Moment
Discovery Year
Parity-

Decay ModeIntensity
α (α emission)
SF (spontaneous fission)

226Am

Mass Number226
Neutron Number131
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin
Quadrupole Moment
Discovery Year
Parity

Decay ModeIntensity
α (α emission)
SF (spontaneous fission)

227Am

Mass Number227
Neutron Number132
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin9/2
Quadrupole Moment
Discovery Year
Parity-

Decay ModeIntensity
α (α emission)
SF (spontaneous fission)

228Am

Mass Number228
Neutron Number133
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin
Quadrupole Moment
Discovery Year
Parity

Decay ModeIntensity
α (α emission)
SF (spontaneous fission)

229Am

Mass Number229
Neutron Number134
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
1.8 ± 1.5 s
Spin5/2
Quadrupole Moment
Discovery Year2015
Parity-

Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)

230Am

Mass Number230
Neutron Number135
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
40 ± 9 s
Spin1
Quadrupole Moment
Discovery Year2003
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ SF (β+-delayed fission)30%

231Am

Mass Number231
Neutron Number136
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin5/2
Quadrupole Moment
Discovery Year
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)
α (α emission)

232Am

Mass Number232
Neutron Number137
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
1.31 ± 0.04 m
Spin1
Quadrupole Moment
Discovery Year1967
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)97%
α (α emission)
β+ SF (β+-delayed fission)0.069%

233Am

Mass Number233
Neutron Number138
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
3.2 ± 0.8 m
Spin5/2
Quadrupole Moment
Discovery Year2000
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)
α (α emission)4.5%

234Am

Mass Number234
Neutron Number139
Relative Atomic Mass
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
2.32 ± 0.08 m
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)0.039%
β+ SF (β+-delayed fission)0.0066%

235Am

Mass Number235
Neutron Number140
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
10.3 ± 0.6 m
Spin5/2
Quadrupole Moment
Discovery Year1996
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.6%
α (α emission)0.4%

236Am

Mass Number236
Neutron Number141
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
3.6 ± 0.1 m
Spin5
Quadrupole Moment
Discovery Year1998
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)4%

237Am

Mass Number237
Neutron Number142
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
73.6 ± 0.8 m
Spin5/2
Quadrupole Moment
Discovery Year1970
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.975%
α (α emission)0.025%

238Am

Mass Number238
Neutron Number143
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
98 ± 3 m
Spin1
Quadrupole Moment
Discovery Year1950
Parity+

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)1%

239Am

Mass Number239
Neutron Number144
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
11.9 ± 0.1 h
Spin5/2
Quadrupole Moment
Discovery Year1949
Parity-

Decay ModeIntensity
ϵ (electron capture)99.99%
α (α emission)0.01%

240Am

Mass Number240
Neutron Number145
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
50.8 ± 0.3 h
Spin3
Quadrupole Moment
Discovery Year1949
Parity-

Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)1.9%

241Am

Mass Number241
Neutron Number146
Relative Atomic Mass
G-Factor
0.64 ± 0.004
Abundance
Radioactivity☢️ Radioactive
Half Life
432.6 ± 0.6 y
Spin5/2
Quadrupole Moment
4.34 ± 0.05
Discovery Year1949
Parity-

Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)3.6%

242Am

Mass Number242
Neutron Number147
Relative Atomic Mass
G-Factor
0.3854 ± 0.0017
Abundance
Radioactivity☢️ Radioactive
Half Life
16.02 ± 0.02 h
Spin1
Quadrupole Moment
-2.4 ± 0.4
Discovery Year1949
Parity-

Decay ModeIntensity
β (β decay)82.7%
ϵ (electron capture)17.3%

243Am

Mass Number243
Neutron Number148
Relative Atomic Mass
G-Factor
0.608 ± 0.004
Abundance
Radioactivity☢️ Radioactive
Half Life
7.35 ± 0.009 ky
Spin5/2
Quadrupole Moment
4.32 ± 0.06
Discovery Year1950
Parity-

Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)3.7%

244Am

Mass Number244
Neutron Number149
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
10.01 ± 0.03 h
Spin6
Quadrupole Moment
Discovery Year1950
Parity-

Decay ModeIntensity
β (β decay)100%

245Am

Mass Number245
Neutron Number150
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
2.05 ± 0.01 h
Spin5/2
Quadrupole Moment
Discovery Year1955
Parity+

Decay ModeIntensity
β (β decay)100%

246Am

Mass Number246
Neutron Number151
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
39 ± 3 m
Spin7
Quadrupole Moment
Discovery Year1955
Parity-

Decay ModeIntensity
β (β decay)100%

247Am

Mass Number247
Neutron Number152
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
23 ± 1.3 m
Spin5/2
Quadrupole Moment
Discovery Year1967
Parity

Decay ModeIntensity
β (β decay)100%

248Am

Mass Number248
Neutron Number153
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin3
Quadrupole Moment
Discovery Year
Parity+

Decay ModeIntensity
β (β decay)

249Am

Mass Number249
Neutron Number154
Relative Atomic Mass
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin5/2
Quadrupole Moment
Discovery Year
Parity

Decay ModeIntensity
β (β decay)
Americium microscope

History

Americium-241 was first identified in 1944 by Glenn T. Seaborg, Ralph A. James, Leon O. Morgan and Albert Ghiorso at the metallurgical laboratory at the University of Chicago. It was produced by irradiating plutonium with neutrons during the Manhattan Project. Americium was first isolated as a pure compound by Burris Cunningham in 1945, at the University of Chicago. Named after America

DiscoverersG.T.Seaborg, R.A.James, L.O.Morgan, A.Ghiorso
Discovery LocationUnited States
Discovery Year1945
Etymology (Name Origin)Named for the American continent, by analogy with europium.
Pronunciationam-er-ISH-i-em (English)
Americium is harmful due to its radioactivity
Americium often enters landfills from discarded smoke detectors

Uses

Americium is used in commercial ionization chamber smoke detectors, as well as in neutron sources and industrial gauges. Americium-241 has been used as a portable source of both gamma rays and alpha particles for a number of medical and industrial uses. It is also used as a target material in nuclear research to make even heavier elements. Americium-241 is currently used in smoke detectors.

Sources

Produced by bombarding plutonium with neutrons.

Abundance
Abundance in Earth's crust
Natural Abundance (Oceans)
Natural Abundance (Human Body)
0 %
Natural Abundance (Meteor)
0 %
Natural Abundance (Sun)
0 %
Abundance in Universe
0 %

Nuclear Screening Constants

Also Known As

  • Am
  • element 95

Translations

  • Frenchaméricium
  • GermanAmericium
  • Afrikaansamerikium
  • Amharicአሜሪኪየም
  • Arabicأمريسيوم
  • AzerbaijaniAmerisium
  • BelarusianАмерыцый
  • Bulgarianамериций
  • Banglaঅ্যামারিসিয়াম
  • Bosnianamericij
  • Catalanamerici
  • CherokeeᎠᎺᎵᏏᏯᎻ
  • CorsicanAmericiu
  • Czechamericium
  • ChuvashАмерици
  • WelshAmericiwm
  • Danishamericium
  • Greekαμερίκιο
  • Esperantoamericio
  • Spanishamericio
  • Estonianameriitsium
  • Basqueamerizio
  • Persianامریسیم
  • Finnishamerikium
  • FriulianAmerici
  • IrishAimeiriciam
  • Galicianamericio
  • GuaraniAmerísio
  • ManxAmericium
  • Hakka Chineseamericium
  • Hebrewאמריציום
  • Fiji HindiAmericium
  • Croatianamericij
  • Haitian CreoleAmerisyòm
  • Hungarianamerícium
  • Armenianամերիցիում
  • Interlinguaamericium
  • Indonesianamerisium
  • Idoamericio
  • Italianamericio
  • Japaneseアメリシウム
  • Lojbanmerjinme
  • JavaneseAmerisium
  • KazakhАмериций
  • Kannadaಅಮೇರಿಶಿಯಮ್
  • Korean아메리슘
  • KomiАмериций
  • Latinamericium
  • LuxembourgishAmericium
  • LigurianAmeriçio
  • Lithuanianamericis
  • Latvianamerīcijs
  • Malayalamഅമെരിസിയം
  • Mongolianамерици
  • Marathiअमेरिसियम
  • Western MariАмериций
  • MalayAmerisium
  • Burmeseအမေရိစီယမ်
  • Dutchamericium
  • Norwegian Nynorskamericium
  • Polishameryk
  • Portugueseamerício
  • QuechuaAmerisyu
  • Romanianamericiu
  • Russianамериций
  • RusynАмерицій
  • YakutАмерициум
  • Sicilianamericiu
  • Serbo-CroatianAmericijum
  • Slovakamerícium
  • Slovenianamericij
  • Albanianamerici
  • Serbianамерицијум
  • Saterland FrisianAmericium
  • Swedishamericium
  • Tamilஅமெரிகியம்
  • Thaiอะเมริเซียม
  • TagalogAmerisyo
  • Turkishamerikyum
  • Uyghurئامېرىتسىي
  • Ukrainianамерицій
  • Urduامریکیئم
  • VepsAmericii
  • Vietnameseamerici
  • WarayAmerisyo
  • KalmykАмерициүм
  • YorubaAmẹrísíọ̀m
  • Chinese
  • Norwegian Bokmålamericium
  • BretonAmerikiom
  • CebuanoAmerisyo
  • Macedonianамерициум
  • Central Kurdishئەمەریسیۆم
  • Western Panjabiامریکیم
  • Gujaratiઅમેરિસીયમ
  • Odiaଆମେରିକିଅମ
  • PiedmonteseAmerissi
  • TatarАмериций
  • Newariअमेरिसियम
  • Sanskritअमेरिसियम
  • Cantonese
  • Literary Chinese
  • Belarusian (Taraskievica orthography)амэрыц
  • AromanianAmericiu
  • UzbekAmeritsiy
  • Nepaliएमरिशियम
  • KyrgyzАмериций
  • LimburgishAmericium
  • Teluguఅమెరీషియం
  • Malteseameriċju
  • Hindiअमेरिशियम
  • Scottish GaelicAmeireagium
  • Paliअमेरिसियम
  • cdoAmericium
  • Min Nan ChineseAmericium
  • AsturianAmericio
  • Bhojpuriअमेरिसियम
  • English (United Kingdom)americium
  • Chinese (Macao SAR China)
  • Chinese (China)
  • Chinese (Simplified)
  • Chinese (Traditional)
  • Chinese (Hong Kong SAR China)
  • Chinese (Malaysia)
  • Chinese (Singapore)
  • Chinese (Taiwan)
  • Portuguese (Brazil)amerício
  • Lingua Franca Novaamerisio
  • kbpAmɛrɩsɩyɔm
  • TajikАмеритсий
  • Northern FrisianAmeriitsium
  • oloAmericii
  • Georgianამერიციუმი
  • Volapüklamerikin
  • Wu Chinese
  • SardinianAmerìtziu
  • SwahiliAmeriki
  • Moroccan Arabicأميريكيوم
  • Egyptian Arabicامريسيوم
  • Pashtoامېرېسيوم
  • CornishAmerikiom
  • BalineseAmérisium
  • IcelandicAmeríkín
  • OccitanAmerici
  • ZuluIsAmoshi