electronic configuration

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chem the arrangement of electrons in the orbitals of an atom or molecule
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What is electronic configuration?

Electronic configuration is the arrangement of electrons around the nucleus of a particular atom or molecule.

An atom is made of tiny particles called protons, neutrons, and electrons. A neutral atom has the same number of protons and elections. That number is listed as its atomic number on the periodic table of the elements. Electronic configuration tells about the number and position of the atom’s electrons.

We describe electrons as orbiting around the nucleus of an atom, similar to how Saturn’s rings orbit the planet. Electrons orbit around the nucleus in orbitals that can hold a certain number of electrons. There are four types of orbitals (s, p, d, and f), which can hold a set amount of electrons (s=2, p=6, d=10, and f=14).

An atom or molecule can have more than one of each orbital. For example, an atom might have 3 s orbitals and 2 p orbitals. The orbitals are numbered based on how close they are to the nucleus, with orbital 2s being closer than 3s for example.

For all atoms, the orbitals are filled in with electrons in this order:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p. We can use this order combined with an atom’s atomic number (Z) to figure out what its electronic configuration would be.

Why is electronic configuration important?

The term electronic configuration has been used since at least the 1920s. Quantum physicist Niels Bohr is credited with developing a model to show how electrons are positioned around a nucleus. Bohr’s “shell model” was used by later scientists, such as Arnold Sommerfeld, to more precisely determine the exact movements and locations of electrons.

When an atom loses or gains electrons, it becomes electrically charged and is referred to as an ion. An ion can also have an electronic configuration. To show this, we simply take the electronic configuration of the neutral atom and add or subtract electrons from the shells.

Did you know … ?

The periodic table is arranged according to electronic configurations. Those “gaps” at the top of the table are due to the absence of d or p orbitals in elements with low atomic numbers.

What are real-life examples of electronic configuration?

This model shows a simplified recreation of an atom. Electronic configuration explains the way in which the electrons orbit around the nucleus in an atom or molecule.


While electronic configurations are useful for all chemists, this term is often used to test students’ knowledge of chemistry.


What other words are related to electronic configuration?

Quiz yourself!

True or False?

Electron configuration is the arrangement of electrons around the nucleus of an atom.

How to use electronic configuration in a sentence