The orbital diagram is a graphical representation of the electron configuration of the atom. This diagram shows how the electrons in the atom are arranged in different orbitals.

Orbital is the region of space around the nucleus of an atom where electrons are found. To create an orbital diagram, you first need to know the atomic orbitals and the orbital notation for the atom, and also you need to know Hund’s principle.

Table of Contents

What is orbital?

The electrons of the atom revolve around the nucleus in a certain circular path. These circular paths are called orbit (shell). Again, atomic energy shells are subdivided into sub-energy levels. These sub-energy levels are also called orbital.

The most probable region of electron rotation around the nucleus is called the orbital. The sub-energy levels depend on the azimuthal quantum number. It is expressed by ‘l’.

Orbit Number	Value of ‘l’	Number of subshells	Number of orbital	Subshell name	Electrons holding capacity	Electron Configuration
1	0	1	1	1s	2	1s²
2	0 1	2	1 3	2s 2p	2 6	2s² 2p⁶
3	0 1 2	3	1 3 5	3s 3p 3d	2 6 10	3s² 3p⁶ 3d¹⁰
4	0 1 2 3	4	1 3 5 7	4s 4p 4d 4f	2 6 10 14	4s² 4p⁶ 4d¹⁰ 4f¹⁴

Orbital number of the subshell

The value of ‘l’ is from 0 to (n – 1). The sub-energy levels are known as s, p, d, and f.

The orbital number of the s-subshell is one, three in the p-subshell, five in the d-subshell, and seven in the f-subshell. Each orbital can have a maximum of two electrons.

Sub-shell name	Name source	Value of ‘l’	Value of ‘m’ (0 to ± l)	Number of orbital (2l+1)	Electrons holding capacity 2(2l+1)
s	Sharp	0	0	1	2
p	Principal	1	−1, 0, +1	3	6
d	Diffuse	2	−2, −1, 0, +1, +2	5	10
f	Fundamental	3	−3, −2, −1, 0, +1, +2, +3	7	14

Number of electrons in the orbital

The sub-energy level ‘s’ can hold a maximum of two electrons, ‘p’ can hold a maximum of six electrons, ‘d’ can hold a maximum of ten electrons, and ‘f’ can hold a maximum of fourteen electrons.

What is the orbital notation?

The orbital notation is a shorthand system designed to represent the exact positions of the electrons in the atom. This is similar to electron configuration, but numbers are used instead of boxes to represent the positions of the electrons.

This orbital notation system always follows the Aufbau principle. The Aufbau principle is that the electrons present in the atom will first complete the lowest energy orbital and then gradually continue to complete the higher energy orbital.

What is Hund’s principle?

Hund’s principle is a rule that helps to determine how electrons are distributed in orbitals when multiple orbitals of the same energy level are available.

Hund’s principle is that electrons in different orbitals with the same energy would be positioned in such a way that they could be in the unpaired state of maximum number and the spin of the unpaired electrons will be one-way.

For example, we already know that the p-subshell has three orbitals. The orbitals are p_x, p_y, and p_z and each orbital can have a maximum of two electrons. When electrons want to enter the p-subshell, then the first electron will enter the p_x orbital in the clockwise direction.

The second electron will also enter the p_y orbital in the clockwise direction and the third electron will also enter the p_z orbital in the clockwise direction.

Now, when the fourth electron wants to enter the p-subshell, then it will enter the p_x orbital in the anti-clockwise direction.

The fifth electron will also enter the p_y orbital in the anti-clockwise direction and the sixth electron will also enter the p_z orbital in the anti-clockwise direction.

Here, the clockwise direction is expressed by the upper sign (↑) and the anti-clockwise direction by the lower sign (↓). Basically, these two symbols (↑↓) indicate the direction of electron spin.

List of Orbital Diagram for All Elements (1 to 118)

Orbital diagrams are usually represented by boxes. Each box represents an orbital and the arrows within the box represent the position of the electron. The boxes are arranged in order of energy of the orbitals.

The lowest energy orbitals are closest to the nucleus and the higher energy orbitals are progressively further away from the nucleus in order of their energy levels.