What is Isotope? Definition, Meaning & Example
Atoms of the same element that have different numbers of neutrons and therefore different mass numbers.
TL;DR: Atoms of the same element that have different numbers of neutrons and therefore different mass numbers.
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Isotope: Atoms of the same element that have different numbers of neutrons and therefore different mass numbers.
Explanation
Isotopes have the same number of protons (same element) but different numbers of neutrons (different mass). Since chemical properties depend on electrons and protons, isotopes have identical chemical properties but different physical properties and nuclear stability. Some isotopes are radioactive and decay over time, emitting radiation. Carbon-12 and Carbon-14 are isotopes of carbon; while Carbon-12 is stable, Carbon-14 is radioactive and is used for radiocarbon dating. Isotopes have practical applications in medicine, dating, and energy production.
Example
Chlorine has two main isotopes: Chlorine-35 with 18 neutrons and Chlorine-37 with 20 neutrons. Both have 17 protons but different mass numbers due to different neutron counts.
Frequently Asked Questions
Why do isotopes of the same element behave differently?
Chemical behavior depends on electrons and protons, which are the same in isotopes. Physical properties differ because isotopes have different masses due to different neutron counts.
Are all isotopes radioactive?
No, many isotopes are stable and non-radioactive. For example, Oxygen-16 is stable, but some heavier elements have no stable isotopes.
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