s orbitals have no angular momentum, and can be visualized as a spherical cloud of probability densities, with equal probabilities of finding the electron at a given radius from the center of the atom. This probability is zero at the nucleus, goes through a maximum at a radius proportional to the energy of the orbital, and tapers to zero at infinite distance from the nucleus. The exact value of this probability can be calculated via the Schrödinger equation.

This is the first and most basic of electron orbitals. There is one s orbital per electron shell and every shell has an s orbital. The orbital is a sphere around the atomic nucleus. The s stands for sharp.

These orbitals are particularly associated with the chemistry of the alkali metals.