Nuclear isomers

{
  "id": "MLC-T-CHM-008103",
  "term": "Nuclear isomers",
  "field": "Chemistry",
  "definition": "Nuclides that have the same atomic number and mass number but differ in their nuclear energy states and half-lives. These distinct excited states of a nucleus are metastable, meaning they persist for a measurable period before decaying to a lower energy state, often by gamma emission. An example is technetium-99m, widely used in medical imaging.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "nuclide",
    "atomic number",
    "mass number"
  ],
  "references": [
    "PAC, 1982, 54, 1533. 'Glossary of terms used in nuclear analytical chemistry (Provisional)' on page 1545 (https://doi.org/10.1351/pac198254081533)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/nuclear-isomers/"
}