What Is an Orbital in Chemistry?

The atom is the most basic component of all the matter in the world. Atoms are made up of both positively charged protons and negatively charged electrons. Electrons move in large clouds around the nucleus of an atom and are notoriously hard to locate as they travel. Orbitals can be used in chemistry to find out information about atoms and where their electrons can be found.

History

Chemists theorized since the year 1900 that electrons floated in orbits inside of an atom much like planets around the sun. The theoretical physicist Erwin Rudolf Schrödinger posited the mathematical function used for defining atomic orbitals in the early 1920s. In 1925 the American chemist Robert Sanderson Mulliken expanded Schrödinger's idea into the formula still used for finding orbitals by chemists around the world today.

Function

The phrase "electron orbital" actually describes both the area in any atom where electrons move in a pattern and the math used to discover that pattern. Electrons are too small and move too fast to be viewed even by the most powerful of microscopes so orbitals are used to mathematically determine where electrons can be found in an atom at any given point in time.

Features

The number of orbitals in an atom will determine how many electrons it has and what other types of atoms it can bond with to form molecules. Orbitals are a much more precise explanation of the "shells" of electrons described in ionic, covalent or metallic bonding of atoms. The amount of orbitals will also determine many of the chemical properties of the atom.

Types

There are four main types of orbitals, each of which is designated by a single letter and describes the general shape that the orbital has. An "S" orbital moves in a standard circular or sphere shape, a "P" orbital moves in a figure eight shape, a "D" orbital moves around in multiple circles like a clover leaf, and "F" orbitals move in intricate and multifaceted patterns that resemble all of the previous kinds combined.

Considerations

The overall density of an atom will be heavier in the area where electrons are moving which is how orbitals are defined. The exact location of an electron will always be a mystery because of their high rate of speed so an orbital can never be more than a rough guide for a general area where the electron will be found as it travels around the atom.

Resources

• More about atomic orbital resources