Silver-121

Properties and data of the isotope ¹²¹Ag.

Content

General data

Name of the isotope:Silver-121; Ag-121Symbol:¹²¹Ag or 12147AgMass number A:121 (= number of nucleons)Atomic number Z:47 (= number of protons)Neutrons N:74Isotopic mass:120.920125(13) u (atomic weight of Silver-121)Nuclide mass:120.8943431 u (calculated nuclear mass without electrons)Mass excess:-74.40308 MeVMass defect:1.088855288 u (per nucleus)Nuclear binding energy:1014.26216764 MeV (per nucleus)
8.38233196 MeV (average binding energy per nucleon)Separation energy:S_N = 6.823(13) MeV (first neutron)
S_P = 11.412(12) MeV (first proton)Half-life:0.78(2) sDecay constant λ:0.88865023148711 s^-1Specific activity α:4.459647391025 × 10⁺²¹ Bq g^-1
120531010568.26 Ci g^-1Spin and parity:
(nuclear angular momentum)(7/2+)Year of discovery:1982

Radioactive Decay

Half-life T_½ = 0.78(2) s respectively 7.8 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹²¹Cd	99.92 %	6.671(12) MeV
β^-, n	¹²⁰Cd	0.08 %	1.483(13) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 74) and isobaric (same nucleon number A = 121) with Silver-121. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 74	Isobar A = 121
41	¹¹⁵Nb
42	¹¹⁶Mo
43	¹¹⁷Tc	¹²¹Tc
44	¹¹⁸Ru	¹²¹Ru
45	¹¹⁹Rh	¹²¹Rh
46	¹²⁰Pd	¹²¹Pd
47	¹²¹Ag	¹²¹Ag
48	¹²²Cd	¹²¹Cd
49	¹²³In	¹²¹In
50	¹²⁴Sn	¹²¹Sn
51	¹²⁵Sb	¹²¹Sb
52	¹²⁶Te	¹²¹Te
53	¹²⁷I	¹²¹I
54	¹²⁸Xe	¹²¹Xe
55	¹²⁹Cs	¹²¹Cs
56	¹³⁰Ba	¹²¹Ba
57	¹³¹La	¹²¹La
58	¹³²Ce	¹²¹Ce
59	¹³³Pr	¹²¹Pr
60	¹³⁴Nd
61	¹³⁵Pm
62	¹³⁶Sm
63	¹³⁷Eu
64	¹³⁸Gd
65	¹³⁹Tb
66	¹⁴⁰Dy
67	¹⁴¹Ho