Nuklid

Nuklid is the German term for nuclide, a distinct species of atomic nucleus defined by its proton number Z and neutron number N. Each nuclide has a specific mass number A = Z + N and may be in a particular energy state, usually the ground state. Nuclides form the building blocks of all atoms, and their properties determine the behavior of the elements they belong to.

Nuclide notation commonly uses the chemical symbol X with a mass number as a superscript and atomic number as a subscript, for example, ^14_6C for carbon-14. In practice, the more compact form ^14C is widely used. Nuclides with the same Z but different N are called isotopes of the element; isotopes are a subset of nuclides, distinguished by their neutron content.

Stability varies among nuclides. Some are stable and persist indefinitely, while others are radioactive and decay into other nuclides, releasing energy and particles. Decay modes include alpha decay, beta decay, gamma emission, and spontaneous fission. The rate of decay is characterized by the half-life, which can range from fractions of a second to billions of years. Nuclear binding energy plays a key role in stability, reflecting how tightly nucleons are held together within the nucleus.

Nuclides are produced naturally and in laboratories. They occur in stellar processes and cosmic rays, are generated in nuclear reactors and accelerators, or arise from radioactive decay. They have wide applications in medicine, industry, dating methods, energy research, and fundamental nuclear physics.