Tömegszámú

Tömegszámú is a Hungarian term that translates to "mass number" in English, a fundamental concept in nuclear physics and chemistry. It represents the total number of protons and neutrons within an atomic nucleus. This value is crucial for understanding isotopes, which are atoms of the same element (meaning they have the same number of protons) but differ in their number of neutrons, and therefore, in their mass number.

The mass number is denoted by the symbol 'A'. It is determined by summing the atomic number (Z), which is the number of protons, and the neutron number (N), which is the number of neutrons. Thus, the relationship is A = Z + N. For instance, the most common isotope of carbon, carbon-12, has an atomic number of 6 (6 protons) and a neutron number of 6, giving it a mass number of 12. Carbon-14, another isotope, has 6 protons and 8 neutrons, resulting in a mass number of 14.

The mass number is distinct from atomic mass, which is the actual mass of an atom, typically expressed in atomic mass units (amu). While the mass number is an integer, the atomic mass is a fractional value due to the slight mass differences between protons and neutrons and the binding energy of the nucleus. Nevertheless, the mass number provides a good approximation of an atom's mass and is essential for calculations involving nuclear reactions, radioactive decay, and determining isotopic abundance.