Isotopen van mendelevium

Het chemisch element mendelevium (Md), met een atoommassa van ongeveer 258 u, bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element. De 17 radio-isotopen zijn onstabiel en hebben een relatief korte halfwaardetijd (de meeste minder dan een uur).

In de natuur komt geen mendelevium voor: alle isotopen zijn synthetisch bereid in een laboratorium. De eerste synthetische isotoop was ²⁵⁶Md, in 1955.

De kortstlevende isotoop van mendelevium is ²⁴⁵Md, met een halfwaardetijd van ongeveer 0,9 milliseconden. De langstlevende is ²⁵⁸Md, met een halfwaardetijd van 51,5 dagen.

Overzicht

Nuclide	Z (p)	N (n)	Isotopische massa (u)	Halveringstijd	Radioactief verval	Kernspin
	Excitatie-energie
^245Md	101	144	245,08083(35)	0,90(25) ms	SS	(1/2^−)
					${\displaystyle {\ce {{^{245}_{101}Md}->{^{241}_{99}Es}+\,_{2}^{4}\alpha }}}$ (zelden)
^245mMd	200(100) keV			400(200) ms	${\displaystyle {\ce {{^{245m}_{101}Md}->{^{241}_{99}Es}+\,_{2}^{4}\alpha }}}$	(7/2^+)
					${\displaystyle {\ce {{^{245}_{101}Md}->{^{245}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (zelden)
^246Md	101	145	246,08189(35)	1,0(4) s	${\displaystyle {\ce {{^{246}_{101}Md}->{^{242}_{99}Es}+\,_{2}^{4}\alpha }}}$
					${\displaystyle {\ce {{^{246}_{101}Md}->{^{246}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (zelden)
^247Md	101	146	247,08164(35)	1,12(22) s	SS	1/2^−
					${\displaystyle {\ce {{^{247}_{101}Md}->{^{243}_{99}Es}+\,_{2}^{4}\alpha }}}$ (zelden)
^247mMd				± 0,2 s	${\displaystyle {\ce {{^{247m}_{101}Md}->{^{243}_{99}Es}+\,_{2}^{4}\alpha }}}$ (99,99%)
					SS (10^−4%)
^248Md	101	147	248,08282(26)	7(3) s	${\displaystyle {\ce {{^{248}_{101}Md}->{^{248}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (80%)
					${\displaystyle {\ce {{^{248}_{101}Md}->{^{244}_{99}Es}+\,_{2}^{4}\alpha }}}$ (20%)
					SS (0,05%)
^249Md	101	148	249,08301(24)	24(4) s	${\displaystyle {\ce {{^{249}_{101}Md}->{^{245}_{99}Es}+\,_{2}^{4}\alpha }}}$ (60%)	(7/2^−)
					${\displaystyle {\ce {{^{249}_{101}Md}->{^{249}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (40%)
^249mMd	100(100) keV			1,9(9) s		(1/2^−)
^250Md	101	149	250,08442(32)	52(6) s	${\displaystyle {\ce {{^{250}_{101}Md}->{^{250}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (93%)
					${\displaystyle {\ce {{^{250}_{101}Md}->{^{246}_{99}Es}+\,_{2}^{4}\alpha }}}$(7%)
					SS (0,02%)
^251Md	101	150	251,08484(22)	4,0(5) min	${\displaystyle {\ce {{^{251}_{101}Md}->{^{251}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (90%)	7/2^−
					${\displaystyle {\ce {{^{251}_{101}Md}->{^{247}_{99}Es}+\,_{2}^{4}\alpha }}}$ (10%)
^252Md	101	151	252,08656(21)	2,3(8) min	${\displaystyle {\ce {{^{252}_{101}Md}->{^{252}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (50%)
					${\displaystyle {\ce {{^{252}_{101}Md}->{^{248}_{99}Es}+\,_{2}^{4}\alpha }}}$ (50%)
^253Md	101	152	253,08728(22)	12(8) min	${\displaystyle {\ce {{^{253}_{101}Md}->{^{253}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$	7/2^−
					${\displaystyle {\ce {{^{253}_{101}Md}->{^{249}_{99}Es}+\,_{2}^{4}\alpha }}}$
^254Md	101	153	254,08966(11)	10(3) min	${\displaystyle {\ce {{^{254}_{101}Md}->{^{254}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$	(0^−)
					${\displaystyle {\ce {{^{254}_{101}Md}->{^{250}_{99}Es}+\,_{2}^{4}\alpha }}}$ (zelden)
^254mMd	50(100) keV			28(8) min	${\displaystyle {\ce {{^{254}_{101}Md}->{^{254}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$	(3^−)
					${\displaystyle {\ce {{^{254}_{101}Md}->{^{250}_{99}Es}+\,_{2}^{4}\alpha }}}$ (zelden)
^255Md	101	154	255,091083(7)	27(2) min	${\displaystyle {\ce {{^{255}_{101}Md}->{^{255}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (92%)	(7/2^−)
					${\displaystyle {\ce {{^{255}_{101}Md}->{^{251}_{99}Es}+\,_{2}^{4}\alpha }}}$ (8%)
					SS (0,15%)
^256Md	101	155	256,09406(6)	77(2) min	${\displaystyle {\ce {{^{256}_{101}Md}->{^{256}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (89%)	(1^−)
					${\displaystyle {\ce {{^{256}_{101}Md}->{^{252}_{99}Es}+\,_{2}^{4}\alpha }}}$ (11%)
^257Md	101	156	257,095541(3)	5,52(5) uur	${\displaystyle {\ce {{^{257}_{101}Md}+{e^{-}}->{^{257}_{100}Fm}+{\nu }_{e}}}}$ (84,8%)	(7/2^−)
					${\displaystyle {\ce {{^{257}_{101}Md}->{^{253}_{99}Es}+\,_{2}^{4}\alpha }}}$ (15,2%)
					SS (1%)
^258Md	101	157	258,098431(5)	51,5(3) dagen	${\displaystyle {\ce {{^{258}_{101}Md}->{^{254}_{99}Es}+\,_{2}^{4}\alpha }}}$ (99,99%)	(8^−)
					${\displaystyle {\ce {{^{258}_{101}Md}->{^{258}_{102}No}+{e^{-}}+{\bar {\nu }}_{e}}}}$ (0,0015%)
					${\displaystyle {\ce {{^{258}_{101}Md}->{^{258}_{100}Fm}+{e^{+}}+{\nu }_{e}}}}$ (0,0015%)
^258mMd	0(200) keV			57,0(9) min	${\displaystyle {\ce {{^{258}_{101}Md}+{e^{-}}->{^{258}_{100}Fm}+{\nu }_{e}}}}$(70%)	1^−
					SS (20%)
					${\displaystyle {\ce {{^{258}_{101}Md}->{^{258}_{102}No}+{e^{-}}+{\bar {\nu }}_{e}}}}$ (10%)
					${\displaystyle {\ce {{^{258}_{101}Md}->{^{254}_{99}Es}+\,_{2}^{4}\alpha }}}$ (1,2%)
^259Md	101	158	259,10051(22)	1,60(6) uur	SS (98,7%)	7/2^−
					${\displaystyle {\ce {{^{259}_{101}Md}->{^{255}_{99}Es}+\,_{2}^{4}\alpha }}}$ (1,3%)
^260Md	101	159	260,10365(34)	27,8(8) dagen	SS (85%)
					${\displaystyle {\ce {{^{260}_{101}Md}->{^{256}_{99}Es}+\,_{2}^{4}\alpha }}}$ (5%)
					${\displaystyle {\ce {{^{260}_{101}Md}+{e^{-}}->{^{260}_{100}Fm}+{\nu }_{e}}}}$(5%)
					${\displaystyle {\ce {{^{260}_{101}Md}->{^{260}_{102}No}+{e^{-}}+{\bar {\nu }}_{e}}}}$ (3,5%)
^261Md	101	160	261,10572(70)	40 min		7/2^−
^262Md	101	161	262,10887(63)	3 min

Overzicht van isotopen per element

	1																	18
1	H	2	Periodiek systeem										13	14	15	16	17	He
2	Li	Be	De links verwijzen naar isotopen per element										B	C	N	O	F	Ne
3	Na	Mg	3	4	5	6	7	8	9	10	11	12	Al	Si	P	S	Cl	Ar
4	K	Ca	Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn	Ga	Ge	As	Se	Br	Kr
5	Rb	Sr	Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag	Cd	In	Sn	Sb	Te	I	Xe
6	Cs	Ba	↓	Hf	Ta	W	Re	Os	Ir	Pt	Au	Hg	Tl	Pb	Bi	Po	At	Rn
7	Fr	Ra	↓↓	Rf	Db	Sg	Bh	Hs	Mt	Ds	Rg	Cn	Nh	Fl	Mc	Lv	Ts	Og
Lanthaniden			La	Ce	Pr	Nd	Pm	Sm	Eu	Gd	Tb	Dy	Ho	Er	Tm	Yb	Lu
Actiniden			Ac	Th	Pa	U	Np	Pu	Am	Cm	Bk	Cf	Es	Fm	Md	No	Lr

Bronnen

• (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