How do isotopes of an element differ?

Isotopes of an element differ in the number of neutrons in their nuclei, but have the same number of protons.

Isotopes are variants of a particular chemical element that share the same number of protons but have different numbers of neutrons. This means that while they have the same atomic number, they have different mass numbers. For example, carbon has two stable isotopes: carbon-12 and carbon-13. Both have 6 protons, but carbon-12 has 6 neutrons, whereas carbon-13 has 7 neutrons.

The difference in the number of neutrons affects the atomic mass of the isotopes. This is why isotopes of the same element can have slightly different physical properties, such as density and boiling point. However, their chemical properties remain largely the same because chemical behaviour is primarily determined by the number of protons and electrons, which are unchanged among isotopes of the same element.

Some isotopes are stable, while others are radioactive. Radioactive isotopes, or radioisotopes, have unstable nuclei that decay over time, emitting radiation. This property makes them useful in various applications, such as medical imaging, cancer treatment, and carbon dating. For instance, carbon-14 is a radioactive isotope used in radiocarbon dating to determine the age of ancient artefacts.

Understanding isotopes is crucial in fields like chemistry, physics, and environmental science. They help scientists trace chemical pathways, study environmental changes, and even understand the processes happening inside stars. So, while isotopes of an element share many similarities, their differences in neutron number open up a world of scientific possibilities.