Notable Isotopes 
120Te [68 neutrons]
Abundance: 0.096
Stable with 68 neutrons
122Te [70 neutrons]Abundance: 2.603%
Stable with 70 neutrons
123Te [71 neutrons]Abundance: 0.908%
Half life: 1.0 x 1013 years [ Electron Capture ]
Decay Energy: 0.051 MeVDecays to 123Sb.
124Te [72 neutrons]Abundance: 4.816%
Stable with 72 neutrons
125Te [73 neutrons]Abundance: 7.139%
Stable with 73 neutrons
126Te [74 neutrons]Abundance: 18.952%
Stable with 74 neutrons
128Te [76 neutrons]Abundance: 31.687%
Half life: 2.2 x 1024 years [ Double beta decay ]
Decay Energy: 0.867 MeVDecays to 128Xe.
| 128Te has the longest half-llife of any radioactive isotope. |
130Te [78 neutrons]Abundance: 33.799%
Half life: 7.9 x 1020 years [ Double beta decay ]
Decay Energy: 2.528 MeVDecays to 130Xe.