Subshells of an Atom are 1s, 2s, 2p, 3s, 3p, 4s and 3d.

An subshell is composed of one orbital. Each orbital can hold a maximum number of two electrons. Therefore, an ssubshell can only contain two electrons. An electron is represented as an arrow in the pictorial representation. The two directions of the arrows indicate two spins of electrons. One has +1/2 spin, the other has -1/2.

A p-subshell is composed of three orbitals. Each orbital can hold a maximum number of two electrons. Therefore, a p-subshell with three orbitals can contain a maximum six electrons.

A d-subshell is made up of five d orbitals that can hold a maximum of ten electrons.

The complete electron configuration can be written by denoting how many electrons are contained in an orbital. This superscript is then added to the orbital.

Here, 1s orbital has 2 electrons, 2s orbital has 2 electrons and 2p orbitals have 6 electrons. 3s orbital has 2 electrons, 4s orbital has one electron, 3p orbitals have 6 electrons, and last 3d orbitals have 5 electrons.

The complete electron configuration will then be written as

1s²2s²2p⁶3s²3p⁶4s¹3d⁵

^{The atomic number of an element is equal to its total number of electrons within the neutral atom. If the configuration is a neutral atom, then the total number electrons in that atom would be (2+2+6+2+6+1+5 = 24,) 24 The element’s atomic number is therefore 24.}

^{Chromium (Cr), the element with the atomic numbers 24 is}

^{Name of element: Chromium}