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  1. Isotope - Wikipedia

    From left to right, the isotopes are protium (1 H) with 0 neutrons, deuterium (2 H) with 1 neutron, and tritium (3 H) with 2 neutrons. Isotopes are distinct nuclear species (or nuclides) of the same chemical …

  2. Isotope | Examples & Definition | Britannica

    Dec 12, 2025 · What is an isotope? An isotope is one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical …

  3. What Is an Isotope? Definition and Examples

    Sep 13, 2019 · An isotope is one of two or more forms of an element that have the same number of protons but different numbers of neutrons in the nucleus. Because they have the same number of …

  4. What is an Isotope? - ChemTalk

    An isotope is an atom that has the same number of protons and a different number of neutrons. The atom is still considered the same element (still contains the same number of protons) as before but …

  5. Isotope Basics | NIDC: National Isotope Development Center

    Isotopes are atoms of the same element that have the same number of protons (i.e., atomic number, "Z") but a different number of neutrons, meaning that their mass number, "A", varies. Take hydrogen, …

  6. What are Isotopes? | IAEA

    Aug 19, 2022 · Like everything we see in the world, isotopes are a type of atom, the smallest unit of matter that retains all the chemical properties of an element. Isotopes are forms of a chemical …

  7. What Are Isotopes? Atomic Structure and Isotope Notation ...

    Forms of the same element that have different numbers of neutrons are referred to as isotopes. The three forms of hydrogen are referred to as the isotopes of hydrogen. Nearly every element has two or …