What is Isotope? Isotopes are two or more types of atoms with the same atomic number (number of protons in their nuclei) and periodic table position but distinct nucleon numbers (mass numbers) due to differing numbers of neutrons in their nuclei. While all isotopes of the same element have nearly identical chemical properties, their atomic mass and physical attributes differ.
The term isotope is derived from the Greek roots isos (o “equal”) and topos (“place”), which signify “the same location.” As a result, different isotopes of a single element occupy the same spot on the periodic table. Margaret Todd, a Scottish doctor, and journalist identify the term to chemist Frederick Soddy in 1913.
The atomic number is called the number of protons in the nucleus of an atom, which is equal to the number of electrons in a neutral (non-ionized) atom. Each atomic number indicates a specific element, but not an isotope; the number of neutrons in an atom of a specific component can vary widely. The mass number of an atom is identified by the number of nucleons (both protons and neutrons) in its nucleus, and each isotope of a specific element has a distinct mass number.
Carbon-12, carbon-13, and carbon-14, for example, are three carbon isotopes with mass numbers of 12, 13, and 14, accordingly. Carbon has an atomic number of 6, which indicates that every carbon atom has 6 protons, giving these isotopes neutron numbers of 6, 7, and 8, accordingly.