What are isotopes and how do they differ?

Isotopes are variants of a chemical element that have the same number of protons but different numbers of neutrons.

Isotopes are a fascinating aspect of chemistry that delve into the atomic structure of elements. Every chemical element is defined by the number of protons in its nucleus, which is known as the atomic number. However, the number of neutrons in the nucleus can vary, and these variations are what we call isotopes. For example, carbon-12 and carbon-14 are both isotopes of carbon, with the same number of protons (6) but different numbers of neutrons (6 and 8, respectively).

The difference in the number of neutrons does not affect the chemical properties of the element, as these are determined by the number of electrons, which equals the number of protons in a neutral atom. However, it does affect the atomic mass. This is why the atomic mass of an element that you see on the periodic table is usually a decimal number - it's a weighted average of the masses of the naturally occurring isotopes.

Isotopes can be stable or unstable. Stable isotopes do not change over time, while unstable isotopes, also known as radioisotopes, undergo radioactive decay. This process can release various types of radiation, which can be detected and measured. This property is utilised in many scientific and medical applications. For example, carbon-14 is used in radiocarbon dating to determine the age of ancient organic materials, and iodine-131 is used in the treatment of thyroid cancer.

In summary, isotopes provide a deeper understanding of the atomic structure and offer a wide range of practical applications. They are a testament to the complexity and versatility of the elements that make up our universe.