Nobelium-253m

Properties and data of the isotope ^253mNo.

Contents

General data

Name of the isotope:Nobelium-253m; No-253mSymbol:^253mNo or 253m102NoMass number A:253 (= number of nucleons)Atomic number Z:102 (= number of protons)Neutrons N:151Isotopic mass:253.090563(7) u (atomic weight of Nobelium-253m)
Excitation energy: 167.5(5) keVNuclide mass:253.0346163 u (calculated nuclear mass without electrons)Mass excess:84.35889 MeVMass defect:2.01599258 u (per nucleus)Nuclear binding energy:1877.88499231 MeV (per nucleus)
7.42247033 MeV (average binding energy per nucleon)Half-life:31.1(21) μsDecay constant λ:22287.690693246 s^-1Specific activity α:5.305123035471 × 10⁺²⁵ Bq g^-1
1.433817036613 × 10⁺¹⁵ Ci g^-1Spin and parity:
(nuclear angular momentum)5/2+

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
²⁵³No		1.62(15) min	(9/2-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 151) and isobaric (same nucleon number A = 253) with Nobelium-253m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 151	Isobar A = 253
92	²⁴³U
93	²⁴⁴Np
94	²⁴⁵Pu
95	²⁴⁶Am
96	²⁴⁷Cm
97	²⁴⁸Bk	²⁵³Bk
98	²⁴⁹Cf	²⁵³Cf
99	²⁵⁰Es	²⁵³Es
100	²⁵¹Fm	²⁵³Fm
101	²⁵²Md	²⁵³Md
102	²⁵³No	²⁵³No
103	²⁵⁴Lr	²⁵³Lr
104	²⁵⁵Rf	²⁵³Rf
105	²⁵⁶Db