40 Examples of Isotopes


In chemistry they talk about isotopes to refer to those atoms that are of the same element but that, despite having the same atomic number (that is, with the same number of protons in the nucleus), their mass number (sum of protons and neutrons) is different. For instance: uranium, thallium, lead, mercury.

Isotopes, then, do not have the same neutron number. This implies that an atom can have several isotopes and still remain the same chemical element. For example, the protium (1H), deuterium (2H) and tritium (3H) are isotopes of the element hydrogen (H). The number in the upper left of the chemical element symbol represents the mass number of the isotope.

Generally, elements have several isotopes and are only 21 the elements that have only one natural isotope. On the other hand, from radioactive processes, man has managed to create many isotopes artificially, although these are characterized by being much more unstable than natural ones and their useful life is also much shorter.

The concept of isotope was created in 1911 by Frederick soddy, an English chemist and professor, when he managed to corroborate that atoms had the same chemical properties.

Classification of isotopes

Isotopes can be classified into several groups:

  • Stable. They have a very long half-life (time required for half the nuclei of a sample of an isotope to disintegrate), so that their disintegration over time is not perceived.
  • Unstable. Also known as “radioactive” (they have radioactive properties), they have a ratio of protons and neutrons that does not allow the stability of the nucleus of the atom to be maintained. These isotopes go through a stage in which they disintegrate and their excess energy is emitted in the form of alpha, beta or gamma radiation.
  • Natural. They are the ones found in nature.
  • Artificial. They are what are generated in laboratories or nuclear power plants.

Isotope Examples

Below is a list with some isotopes, as an example:

  1. Uranium-234 (2. 3. 4OR)
  2. Thallium-203 (203Tl)
  3. Lead-207 (207Pb)
  4. Mercury-201 (201Hg)
  5. Iridium-191 (191To go)
  6. Potassium-39 (39K)
  7. Rhenium-185 (185Re)
  8. Zinc-67 (67Zn)
  9. Hafnium-176 (176Hf)
  10. Samarium-147 (147Ye)
  11. Germanium-74 (74Ge)
  12. Dysprosium-163 (163Dy)
  13. Europium-151 (151Eu)
  14. Krypton-80 (80Kr)
  15. Titanium-49 (49You)
  16. Gadolinium-156 (156Gd)
  17. Erbium-166 (166Er)
  18. Sulfur-32 (32S)
  19. Nickel-61 (61Neither)
  20. Carbon-12 (12C)
  21. Neodomium-142 (142Nd)
  22. Cerium-140 (140EC)
  23. Xenon-131 (131Xe)
  24. Tin-122 (122Sn)
  25. Iron-56 (56Faith)
  26. Cadmium-113 (113CD)
  27. Silver-107 (107Ag)
  28. Ruthenium-102 (102Ru)
  29. Lithium-6 (6Li)
  30. Oxygen-18 (18OR)
  31. Chromium-52 (52Cr)
  32. Tellurium-124 (124Tea)
  33. Zirconium-94 (94Zr)
  34. Argon-40 (40Ar)
  35. Neon-22 (22Ne)
  36. Boron-11 (elevenB)
  37. Helium-4 (4He)
  38. Molybdenum-100 (100Mo)
  39. Cerium-140 (140EC)
  40. Tungsten-183 (183W)