Atomimassaluvusta

Atomimassaluvusta is a Finnish term that translates to "mass number" in English. It refers to the total number of protons and neutrons in the nucleus of an atom. This number is a fundamental characteristic of an atomic nucleus and is often denoted by the letter A.

The mass number is distinct from the atomic number, which represents only the number of protons in the nucleus. Protons and neutrons, collectively known as nucleons, contribute significantly to the mass of an atom. Therefore, the mass number provides a good approximation of the atom's atomic mass.

Different isotopes of the same element have the same atomic number but can have different mass numbers due to variations in the number of neutrons. For example, Carbon-12 has 6 protons and 6 neutrons, giving it a mass number of 12. Carbon-14, another isotope of carbon, has 6 protons and 8 neutrons, resulting in a mass number of 14.

The mass number is usually written as a superscript to the left of the element's chemical symbol, or after the element's name followed by a hyphen. For instance, Helium-4 is represented as $^{4}$He. Understanding the mass number is crucial in nuclear physics and chemistry for studying isotopes, nuclear reactions, and radioactive decay.