Arsenic-77

Properties and data of the isotope ⁷⁷As.

Content

General data

Name of the isotope:Arsenic-77; As-77Symbol:⁷⁷As or 7733AsMass number A:77 (= number of nucleons)Atomic number Z:33 (= number of protons)Neutrons N:44Isotopic mass:76.9206476(18) u (atomic weight of Arsenic-77)Nuclide mass:76.9025451 u (calculated nuclear mass without electrons)Mass excess:-73.91628 MeVMass defect:0.71883476000001 u (per nucleus)Nuclear binding energy:669.59026593 MeV (per nucleus)
8.69597748 MeV (average binding energy per nucleon)Separation energy:S_N = 9.6963(19) MeV (first neutron)
S_P = 7.9924(17) MeV (first proton)Half-life:38.79(5) hDecay constant λ:4.963673201569 × 10^-6 s^-1Specific activity α:3.933149895071 × 10⁺¹⁶ Bq g^-1
1063013.4851545 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Magnetic dipole moment:μ(μ_N) = +1.2940(13)Nuclear g-factor:g_l = 0.86266666666667Year of discovery:1951

Radioactive Decay

Half-life T_½ = 38.79(5) h (hours) respectively 1.39644 × 10⁵ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁷⁷Se	100 %	0.6832(17) MeV

Parent Nuclides

Direct parent isotope is: ⁷⁷Ge.

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
^77mAs	475.48(4) keV	114.0(25) μs	9/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 44) and isobaric (same nucleon number A = 77) with Arsenic-77. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 44	Isobar A = 77
23	⁶⁷V
24	⁶⁸Cr
25	⁶⁹Mn
26	⁷⁰Fe
27	⁷¹Co
28	⁷²Ni	⁷⁷Ni
29	⁷³Cu	⁷⁷Cu
30	⁷⁴Zn	⁷⁷Zn
31	⁷⁵Ga	⁷⁷Ga
32	⁷⁶Ge	⁷⁷Ge
33	⁷⁷As	⁷⁷As
34	⁷⁸Se	⁷⁷Se
35	⁷⁹Br	⁷⁷Br
36	⁸⁰Kr	⁷⁷Kr
37	⁸¹Rb	⁷⁷Rb
38	⁸²Sr	⁷⁷Sr
39	⁸³Y	⁷⁷Y
40	⁸⁴Zr	⁷⁷Zr
41	⁸⁵Nb
42	⁸⁶Mo
43	⁸⁷Tc
44	⁸⁸Ru
45	⁸⁹Rh
46	⁹⁰Pd