The term "orbital" in atomic physics can be a bit misleading, as it does not refer to an electron orbiting the nucleus in the same way as a planet orbits the sun. The concept of electrons orbiting the nucleus in well-defined paths, like planets in the solar system, was proposed by the Bohr model of the atom. However, this model was later replaced by the quantum mechanical model, which introduced the concept of atomic orbitals.
In quantum mechanics, electrons are described by wave functions that represent their probability distributions in space. An atomic orbital is a mathematical function that describes the probability of finding an electron in a particular region around the nucleus. The square of the wave function gives the probability density of finding the electron at a specific location.
Atomic orbitals have distinct shapes and energy levels, determined by the quantum numbers. The most commonly known orbitals are the s, p, d, and f orbitals, which have different shapes and orientations. These orbitals are associated with specific energy levels and are populated by electrons according to the Pauli exclusion principle and the Aufbau principle.
Instead of thinking of electrons as particles orbiting the nucleus, it is more accurate to understand them as existing in a cloud of probability within specific regions of space. The concept of atomic orbitals helps to describe and predict the behavior of electrons in atoms based on their quantum mechanical properties.