atómi

Atómi is the term used in several languages to denote the atom, the fundamental unit of matter in chemistry and physics. An atom is the smallest unit of an element that retains the chemical properties of that element. In contemporary science, atoms consist of a central nucleus containing protons and neutrons, surrounded by a cloud of electrons bound by electromagnetic forces. The nucleus, held together by the strong nuclear force, accounts for nearly all the atom’s mass, while the electrons occupy a much larger volume.

The nucleus has a positive charge equal to the number of protons, known as the atomic number Z. The total number of protons plus neutrons gives the mass number A. Atoms can combine with other atoms to form molecules. The electrons are arranged in electron shells or orbitals around the nucleus; their arrangement largely determines an element’s chemical behavior and bonding patterns. Atoms of the same element can have different numbers of neutrons, called isotopes, which may have different nuclear properties and stability.

Historically, the idea of indivisible units appeared in ancient philosophy, while the scientific atomic theory was formulated in the 19th century by Dalton and refined through Thomson’s discovery of the electron and Rutherford’s nuclear model, followed by the quantum mechanical description of electron orbitals.

Applications of atomic science range from chemistry and materials science to medicine and energy. The study of atoms underpins the periodic table, spectroscopy, and various technologies, including imaging methods and nuclear power.