Nobelium-253

Properties and data of the isotope ²⁵³No.

Contents

General data

Name of the isotope:Nobelium-253; No-253Symbol:²⁵³No or 253102NoMass 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-253)Nuclide 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)Separation energy:S_N = 6.584(12) MeV (first neutron)
S_P = 3.44(13) MeV (first proton)Half-life:1.62(15) minDecay constant λ:0.0071311438329212 s^-1Specific activity α:1.697421053530 × 10⁺¹⁹ Bq g^-1
458762446.90014 Ci g^-1Spin and parity:
(nuclear angular momentum)(9/2-)Year of discovery:1967

Radioactive Decay

Half-life T_½ = 1.62(15) min (minutes) respectively 9.72 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	²⁵³Md	45(3) %	3.19(3) MeV
α	²⁴⁹Fm	55(3) %	8.415(4) MeV

Parent Nuclides

Direct parent isotope is: ²⁵⁷Rf.

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
^253mNo	167.5(5) keV	31.1(21) μs	5/2+

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-253. 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