How many electrons are in each orbital?

Each orbital can hold a maximum of two electrons. These two electrons must have opposite spins, following the Pauli Exclusion Principle.

Understanding Orbitals

An orbital is a mathematical function that describes the wave-like behavior of an electron in an atom. It represents the region of space where an electron is most likely to be found.

Key Points:

• Definition: An orbital is a region of space around the nucleus of an atom where there is a high probability of finding an electron.
• Electron Capacity: Each orbital can accommodate a maximum of two electrons.
• Spin: The two electrons in an orbital must have opposite spins, described as spin-up (+1/2) and spin-down (-1/2). This is a consequence of the Pauli Exclusion Principle.

Electron Configuration

The arrangement of electrons within an atom is called its electron configuration. The filling of electrons into orbitals follows specific rules and principles:

Rules and Principles:

1. Aufbau Principle: Electrons first fill the lowest energy orbitals available.
2. Hund's Rule: Within a subshell, electrons individually occupy each orbital before any orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.
3. Pauli Exclusion Principle: No two electrons in an atom can have the same set of four quantum numbers. This means that if two electrons occupy the same orbital (n, l, and ml are the same), they must have different spins (ms).

Examples

To further illustrate, consider these points:

• s-orbital: An s-orbital is spherical and can hold up to 2 electrons.
• p-orbitals: There are three p-orbitals (px, py, pz) in a p-subshell, each capable of holding 2 electrons, for a total of 6 electrons in the p-subshell.
• d-orbitals: There are five d-orbitals in a d-subshell, each capable of holding 2 electrons, for a total of 10 electrons in the d-subshell.

In summary, an orbital is a region of space that can hold a maximum of two electrons, each with opposite spin. This fundamental principle governs the electronic structure of atoms and the formation of chemical bonds.