atoom

Atoom is the Dutch term for atom, the fundamental unit of matter in chemistry and physics. Atoms are the building blocks of elements and can combine to form molecules, which make up all substances.

An atom consists of a dense nucleus containing protons and neutrons, surrounded by electrons in an electron cloud. The nucleus carries a positive charge; electrons are held in orbit by the electromagnetic force. The atomic number Z identifies the element, while the mass number A indicates the total count of nucleons in the nucleus. Isotopes are variants of an element with the same Z but different A.

Historically, the concept developed from philosophical ideas about indivisible matter but was established through experiments in the 19th and 20th centuries. J. J. Thomson discovered the electron; Rutherford's gold foil experiment led to the nuclear model of the atom; Niels Bohr proposed a model with quantized orbits, later refined by the quantum mechanical description where electrons occupy probabilistic orbitals.

In Dutch usage, atoom is common in science education and discourse, with derived terms such as atoommodel (atomic model), atoomnummer (atomic number), and atoommassa (atomic mass). Atoom theory underpins chemistry, physics, materials science, and related disciplines.