neutralatom

A neutral atom is an atom with zero net electric charge, in which the number of protons in the nucleus equals the number of electrons in the neutral state. The nucleus contains protons and neutrons; the electrons occupy orbitals around the nucleus, described by quantum mechanics.

The chemical behavior of a neutral atom is primarily determined by its electron configuration, especially the valence electrons in the outermost shell or subshells. Neutral atoms can lose electrons to form positive ions (cations) or gain electrons to form negative ions (anions); the energy required to remove the outermost electron is the ionization energy.

In many contexts neutral atoms coexist with ions, such as in gases, plasmas, and interstellar matter. They interact through electromagnetic forces, bonding, and van der Waals forces. Spectroscopic lines from neutral atoms (e.g., Fe I) are used to study stars and planetary atmospheres.

Neutral atoms can be produced and studied with techniques that avoid overall charge, such as cooling and trapping using lasers and magnetic fields, thermal effusion, or neutralization of ionic beams. They are difficult to confine with static electric fields alone, which is why optical and magnetic methods are used.

Applications of neutral atoms include chemical analysis, astrophysical spectroscopy, and precision measurements. Neutral atoms serve in optical lattice clocks (e.g., strontium, ytterbium) and in neutral-atom quantum computing platforms that use arrays of individually controlled atoms.