SOrbitale

sOrbitale denotes the s-type atomic orbital in quantum chemistry and atomic physics. It is defined by orbital angular momentum quantum number l = 0 and exhibits spherical symmetry around the nucleus. For each principal quantum number n ≥ 1 there exists an s orbitale, commonly labeled 1s, 2s, 3s, and so on. Each such orbital can hold up to two electrons with opposite spins.

In the hydrogen-like model, the s orbitale separates into a radial part R_n0(r) and an angular part Y_0^0(θ,φ). The angular part is constant, giving a purely spherical shape with no angular nodes. The radial part has n−1 nodes, and the radial probability distribution can peak near the nucleus for low n or further out for higher n.

Electron occupancy follows the Pauli exclusion principle, so an s orbitale can accommodate two electrons with opposite spins. In multi-electron atoms, s orbitales are typically lower in energy than p orbitales within the same principal shell due to penetration effects. The basic filling order follows the Aufbau principle, with 1s, 2s, 3s, and so on, though energy gaps can be influenced by electron shielding and subshell interactions. In hydrogen, all s orbitales with the same n are degenerate.

Chemically, s orbitales often contribute to valence and bonding, especially the outermost s orbitale in alkali and alkaline earth metals. The concept of the s orbitale provides a foundation for molecular orbital theory and spectroscopy, and serves as a standard reference point in atomic structure education.