At different times after the accident, different isotopes were responsible for the majority of the external dose.

Radium has 25 different known isotopes, four of which are found in nature, with Ra being the most common.

The mass number is different for each different isotope of a chemical element.

These varieties are different isotopes of the same element, and they can come in different grades, or strengths.

Plutonium has at least 15 different isotopes, all of which are radioactive.

The different isotopes of carbon do not differ appreciably in their chemical properties.

To do so, they took claw clippings from the birds and analyzed them for different isotopes of hydrogen.

A different isotope, plutonium 239, is used to build nuclear weapons.

The two activities were different isotopes of the same undiscovered element no. 91.

The average mass of a population of atoms that have different isotopes might not be a whole number.