kokonaisnukleonimäärän

Kokonaisnukleonimäärä, often translated as total nucleon number or mass number, is a fundamental concept in nuclear physics. It represents the total count of protons and neutrons within an atomic nucleus. Protons and neutrons are collectively known as nucleons. The symbol commonly used for the total nucleon number is 'A'. This number is crucial for identifying an isotope of a chemical element, as different isotopes of the same element have the same number of protons (atomic number, Z) but varying numbers of neutrons, thus resulting in different total nucleon numbers.

The total nucleon number is determined by summing the number of protons and neutrons in the nucleus. For example, a carbon-12 atom has 6 protons and 6 neutrons, so its total nucleon number is 12. Similarly, carbon-14 has 6 protons and 8 neutrons, giving it a total nucleon number of 14. This value directly influences an atom's mass, as protons and neutrons contribute significantly to it. The total nucleon number is always an integer and is typically shown as a superscript to the left of the element's chemical symbol, such as $^{12}$C or $^{14}$C. It is a key identifier in nuclear reactions and radioactive decay processes.