# Isotopen van americium

Het chemisch element americium (Am), met een atoommassa van 237,0482 u, bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element. De 18 radio-isotopen zijn onstabiel en hebben een relatief korte halfwaardetijd (de meeste minder dan een minuut).
In de natuur komt geen americium voor: alle isotopen zijn synthetisch bereid in een laboratorium. De eerste synthetische isotoop was $^{241}$Am, in 1944.
De kortstlevende isotoop van americium is $^{225}$Am, met een halfwaardetijd van ongeveer 3 milliseconden. De langstlevende is $^{243}$Am, met een halfwaardetijd van 7370 jaar.

## Overzicht

| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin |
| Kernspin |||
| $^{231}$Am | 95 | 136 | 231,04556(32) | 30 s | β$^+$ | $^{231}$Pu | |
| $^{231}$Am | 95 | 136 | 231,04556(32) | 30 s | α (zelden) | $^{227}$Np | |
| $^{232}$Am | 95 | 137 | 232,04659(32) | 79(2) s | β$^+$ (98%) | $^{232}$Pu | |
| $^{232}$Am | 95 | 137 | 232,04659(32) | 79(2) s | α (2%) | $^{228}$Np | |
| $^{232}$Am | 95 | 137 | 232,04659(32) | 79(2) s | β$^+$, SS (0,069%) | | |
| $^{233}$Am | 95 | 138 | 233,04635(11) | 3,2(8) min | β$^+$ | $^{233}$Pu | |
| $^{233}$Am | 95 | 138 | 233,04635(11) | 3,2(8) min | α | $^{229}$Np | |
| $^{234}$Am | 95 | 139 | 234,04781(22) | 2,32(8) min | β$^+$ (99,95%) | $^{234}$Pu | |
| $^{234}$Am | 95 | 139 | 234,04781(22) | 2,32(8) min | α (0,04%) | $^{230}$Np | |
| $^{234}$Am | 95 | 139 | 234,04781(22) | 2,32(8) min | β$^+$, SS (0,0066%) | | |
| $^{235}$Am | 95 | 140 | 235,04795(13) | 9,9(5) min | β$^+$ | $^{235}$Pu | 5/2$^−$ |
| $^{235}$Am | 95 | 140 | 235,04795(13) | 9,9(5) min | α (zelden) | $^{231}$Np | 5/2$^−$ |
| $^{236}$Am | 95 | 141 | 236,04958(11) | 3,6(1) min | β$^+$ | $^{236}$Pu | |
| $^{236}$Am | 95 | 141 | 236,04958(11) | 3,6(1) min | α | $^{232}$Np | |
| $^{237}$Am | 95 | 142 | 237,05000(6) | 73,0(10) min | β$^+$ (99,97%) | $^{237}$Pu | 5/2$^−$ |
| $^{237}$Am | 95 | 142 | 237,05000(6) | 73,0(10) min | α (0,025%) | $^{233}$Np | 5/2$^−$ |
| $^{238}$Am | 95 | 143 | 238,05198(5) | 98(2) min | β$^+$ | $^{238}$Pu | 1$^+$ |
| $^{238}$Am | 95 | 143 | 238,05198(5) | 98(2) min | α (10$^{−4}$%) | $^{234}$Np | 1$^+$ |
| $^{238m}$Am | 2500(200) keV | 2500(200) keV | 2500(200) keV | 35(10) µs | | | |
| $^{239}$Am | 95 | 144 | 239,0530245(26) | 11,9(1) uur | EV (99,99%) | $^{236}$Pu | 5/2$^−$ |
| $^{239}$Am | 95 | 144 | 239,0530245(26) | 11,9(1) uur | α (0,01%) | $^{235}$Np | 5/2$^−$ |
| $^{239m}$Am | 2500(200) keV | 2500(200) keV | 2500(200) keV | 163(12) ns | | | (7/2$^+$) |
| $^{240}$Am | 95 | 145 | 240,055300(15) | 50,8(3) uur | β$^+$ | $^{240}$Pu | (3$^−$) |
| $^{240}$Am | 95 | 145 | 240,055300(15) | 50,8(3) uur | α (1,9 × 10$^{−4}$%) | $^{236}$Np | (3$^−$) |
| $^{241}$Am | 95 | 146 | 241,0568291(20) | 432,2(7) jaar | α | $^{237}$Np | 5/2$^−$ |
| $^{241}$Am | 95 | 146 | 241,0568291(20) | 432,2(7) jaar | CV (7,4 × 10$^{−10}$%) | $^{207}$Tl, $^{34}$Si | 5/2$^−$ |
| $^{241}$Am | 95 | 146 | 241,0568291(20) | 432,2(7) jaar | SS (4,3 × 10$^{−10}$%) | | 5/2$^−$ |
| $^{241m}$Am | 2200(100) keV | 2200(100) keV | 2200(100) keV | 1,2(3) µs | | | |
| $^{242}$Am | 95 | 147 | 242,0595492(20) | 16,02(2) uur | β$^−$ (82,7%) | $^{242}$Cm | 1$^−$ |
| $^{242}$Am | 95 | 147 | 242,0595492(20) | 16,02(2) uur | EV (17,3%) | $^{242}$Pu | 1$^−$ |
| $^{242m1}$Am | 48,60(5) keV | 48,60(5) keV | 48,60(5) keV | 141(2) jaar | IT (99,54%) | $^{242}$Am | 5$^−$ |
| $^{242m1}$Am | 48,60(5) keV | 48,60(5) keV | 48,60(5) keV | 141(2) jaar | α (0,46%) | $^{238}$Np | 5$^−$ |
| $^{242m1}$Am | 48,60(5) keV | 48,60(5) keV | 48,60(5) keV | 141(2) jaar | SS (1,5 × 10$^{−8}$%) | | 5$^−$ |
| $^{242m2}$Am | 2200(80) keV | 2200(80) keV | 2200(80) keV | 14,0(10) ms | | | (2$^+$, 3$^−$) |
| $^{243}$Am | 95 | 148 | 243,0613811(25) | 7,370(40) jaar | α | $^{239}$Np | 5/2$^−$ |
| $^{243}$Am | 95 | 148 | 243,0613811(25) | 7,370(40) jaar | SS (3,7 × 10$^{−9}$%) | | 5/2$^−$ |
| $^{244}$Am | 95 | 149 | 244,0642848(22) | 10,1(1) uur | β$^−$ | $^{244}$Cm | (6$^−$) |
| $^{244m}$Am | 86,1(10) keV | 86,1(10) keV | 86,1(10) keV | 26(1) min | β$^−$ (99,96%) | $^{244}$Cm | 1$^+$ |
| $^{244m}$Am | 86,1(10) keV | 86,1(10) keV | 86,1(10) keV | 26(1) min | EV (0,0361%) | $^{244}$Pu | 1$^+$ |
| $^{245}$Am | 95 | 150 | 245,066452(4) | 2,05(1) uur | β$^−$ | $^{245}$Cm | 5/2$^+$ |
| $^{246}$Am | 95 | 151 | 246,069775(20) | 39(3) min | β$^−$ | $^{246}$Cm | (7$^−$) |
| $^{246m1}$Am | 30(10) keV | 30(10) keV | 30(10) keV | 25,0(2) min | β$^−$ (99,99%) | $^{246}$Cm | 2$^−$ |
| $^{246m1}$Am | 30(10) keV | 30(10) keV | 30(10) keV | 25,0(2) min | IT (0,01%) | $^{246}$Am | 2$^−$ |
| $^{246m2}$Am | ± 2000 keV | ± 2000 keV | ± 2000 keV | 73(10) µs | | | |
| $^{247}$Am | 95 | 152 | 247,07209(11) | 23,0(13) min | β$^−$ | $^{247}$Cm | (5/2) |
| $^{248}$Am | 95 | 153 | 248,07575(22) | 3 min | β$^−$ | $^{248}$Cm | |
| $^{249}$Am | 95 | 154 | 249,07848(32) | 1 min | β$^−$ | $^{249}$Cm | |

## Overzicht van isotopen per element

* (en) R.B. Firestone, S.Y. Frank Chu & C.M. Baglin (1999) - Table of Isotopes (online versie van de cd-rom)
* (en) G. Audi, A.H. Wapstra, C. Thibault, J. Blachot & O. Bersillon (2003) - The NUBASE evaluation of nuclear and decay properties, Nuclear Physics A, 729, pp. 3-128
* (en) J.R. de Laeter, J.K. Böhlke, P. De Bièvre, H. Hidaka, H.S. Peiser, K.J.R. Rosman & P.D.P. Taylor (2003) - Atomic weights of the elements. Review 2000 (IUPAC Technical Report), Pure and Applied Chemistry, 75 (6), pp. 683–800
* (en) M.E. Wieser (2006) - Atomic weights of the elements 2005 (IUPAC Technical Report), Pure and Applied Chemistry, 78 (11), pp. 2051–2066
* (en) David R. Lide (2004) - CRC Handbook of Chemistry and Physics (85th ed.), hoofdstuk 11, CRC Press - ISBN 978-0849304859
$^{229}$Am · $^{230}$Am · $^{231}$Am · $^{232}$Am · $^{233}$Am · $^{234}$Am · $^{235}$Am · $^{236}$Am · $^{237}$Am · $^{238}$Am · $^{238m}$Am · $^{239}$Am · $^{239m}$Am · $^{240}$Am · $^{241}$Am · $^{241m}$Am · $^{242}$Am · $^{242m1}$Am · $^{242m2}$Am · $^{243}$Am · $^{244}$Am · $^{244m}$Am · $^{245}$Am · $^{246}$Am · $^{246m1}$Am · $^{246m2}$Am · $^{247}$Am · $^{248}$Am · $^{249}$Am