Isotopes are atoms of the same element that have different numbers of neutrons. This means that they have the same number of protons and electrons, but different mass numbers.
Isotopes are represented by the element's symbol followed by its mass number. For example, carbon-12 and carbon-14 are two isotopes of carbon, with mass numbers of 12 and 14 respectively.
Isotopes exist because of natural variations in the number of neutrons in an element's nucleus. This can be due to radioactive decay or different processes during the formation of the element.
Isotopes differ from each other in terms of their mass number, which affects their atomic weight and physical properties. They also have different stability levels, with some isotopes being stable and others being radioactive.
Isotopes are used in various fields of chemistry, such as research, medicine, and industry. They can be used as tracers to study chemical reactions, as markers in medical imaging, and as sources of energy in nuclear reactions.