protonimäärän
Protonimäärään refers to the number of protons in an atomic nucleus. This quantity is fundamental in defining an element and is known as the atomic number, typically denoted by the symbol Z. Every atom of a specific element has the same number of protons. For example, all hydrogen atoms have one proton, all helium atoms have two protons, and all carbon atoms have six protons. The number of protons dictates the element's identity and its chemical properties, as it determines the number of electrons in a neutral atom, which in turn governs how the atom interacts with other atoms. The proton number is also crucial in nuclear physics, influencing nuclear stability and radioactive decay. It is the primary characteristic that distinguishes one element from another on the periodic table. The term is commonly used in Finnish scientific contexts.