Átoma

Átoma is a term used in some Spanish-language contexts to refer to the fundamental unit of matter, more commonly written átomo in standard Spanish. In scientific usage, átomo denotes the smallest unit of an element that retains its chemical properties.

An átomo consists of a dense nucleus containing protons and neutrons, collectively called nucleons, around which electrons are arranged in a probabilistic cloud or orbitals. The nucleus accounts for almost all the atom’s mass, while electrons determine its interactions and chemistry.

The atomic number Z is the number of protons in the nucleus and defines the element (for example, Z = 1 for hydrogen). The mass number A equals protons plus neutrons. Atoms with the same Z but different A are isotopes and often have different masses.

Atomic structure is described by quantum mechanics. Early models evolved from Dalton’s indivisible particles to Rutherford’s nucleus and Bohr’s quantized orbits, to the modern quantum model, which uses electron orbitals and probability distributions to describe electron positions.

Átomo behavior under chemical bonding leads to molecule formation and material properties. The arrangement of electrons governs reactivity and spectra; the periodic table organizes elements by increasing Z and electron configuration, guiding chemistry, physics, and materials science.