"радиоактивностям" meaning in Russian

{
  "forms": [
    {
      "form": "радиоакти́вностям",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "radioaktívnostjam",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "ru",
        "2": "noun form",
        "g": "f-in-p",
        "head": "радиоакти́вностям"
      },
      "expansion": "радиоакти́вностям • (radioaktívnostjam) f inan pl",
      "name": "head"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Russian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "extra": "radioaktívnostʹ",
          "word": "радиоакти́вность"
        }
      ],
      "glosses": [
        "dative plural of радиоакти́вность (radioaktívnostʹ)"
      ],
      "id": "en-радиоактивностям-ru-noun-TyHmNV-z",
      "links": [
        [
          "радиоакти́вность",
          "радиоактивность#Russian"
        ]
      ],
      "tags": [
        "dative",
        "form-of",
        "plural"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[ˌradʲɪɐɐkˈtʲivnəsʲtʲəm]"
    }
  ],
  "word": "радиоактивностям"
}

{
  "forms": [
    {
      "form": "радиоакти́вностям",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "radioaktívnostjam",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "ru",
        "2": "noun form",
        "g": "f-in-p",
        "head": "радиоакти́вностям"
      },
      "expansion": "радиоакти́вностям • (radioaktívnostjam) f inan pl",
      "name": "head"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Russian 7-syllable words",
        "Russian entries with incorrect language header",
        "Russian non-lemma forms",
        "Russian noun forms",
        "Russian terms with IPA pronunciation"
      ],
      "form_of": [
        {
          "extra": "radioaktívnostʹ",
          "word": "радиоакти́вность"
        }
      ],
      "glosses": [
        "dative plural of радиоакти́вность (radioaktívnostʹ)"
      ],
      "links": [
        [
          "радиоакти́вность",
          "радиоактивность#Russian"
        ]
      ],
      "tags": [
        "dative",
        "form-of",
        "plural"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[ˌradʲɪɐɐkˈtʲivnəsʲtʲəm]"
    }
  ],
  "word": "радиоактивностям"
}