Chromium is a metal that belongs to the family of transition metals. It atomic number is 24. It has an atomic weight of 51.99, and it is not poisonous. Chromium is a shiny silver metal with a little bit of blue tinge to it. An electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals. In this post we will see the electron configuration of chromium atom in details
What is an Electron Configuration of Chromium?
The electron configuration of the chromium atom is 1s2 2s2 2p6 3s2 3p6 4s1 3d5 or [Ar] 3d⁵ 4s¹. This means that the chromium atom has one electron in its 1s orbital, two electrons in its 2s orbital, six electrons in its 2p orbitals, two electrons in its 3s orbital, six electrons in its 3p orbitals, one electron in its 4s orbital, and last five electrons in its 3d orbitals. The valence electron of chromium is Six(6).
This is the exceptional case of chromium during electron configuration. This is too many reason given to this exception but the one that is popular is that half filled orbitals / shell is more stable than partially filled orbitals or shell.
So, if you see in chromium you find out that In 4s1 subshell the no. is electron in 4s orbital is one that is half filled,
Again if you see in 3d5 you find our there are again 5 electrons in d orbitals or shell in chromium which is half filled, as i earlier said that half filled is more stable than partially filled orbitals.
Chromium Electron configuration Tabular Form
| Atomic Number | 24 |
| Atomic Mass | 51.99u |
| Ground State Electronic Configuration / Electronic Configuration of chromium (both are same) | 1s2 2s2 2p6 3s2 3p6 4s1 3d5 |
| Excited State Electronic Configuration | Not Possible |
| Abbreviated Form (ground state) | [Ar] 3d⁵ 4s¹ |
| Abbreviated Form (Excited state) | Not Possible |
| Block category | D block |
| Group | 6 |
| State | Solid |
The Ground State Electronic Configurations of Chromium.
The Ground state electronic configuration of chromium is 1s2 2s2 2p6 3s2 3p6 4s1 3d5 which is same as neutral chromium atom. The energy levels are shown in bold. The d-block elements, including chromium, have configurations that correspond to filling the d orbitals in a process called ‘d-subshell pairing’. This results in chromium having five unpaired electrons in its outermost energy level, giving it the designation 5+. Chromium is one of the few elements which can exist in more than one stable oxidation state (valence); +3 and +6 are the most common.
Excited State of chromium electron configuration
As same as ground state electron configuration, the excited state is similar to ground state. The difference is only that we remove the one electron the the S subshell of chromium atom. But in the case of chromium the excited state configuration is not possible because if we remove one electron in 4s subshell then the 4S subshell or orbits becomes vacant which creates unitability to atom. So, the electron configuration of Chromium atom in excited state is not possible.
An Interesting Fact about Chromium
Chromium is an interesting element because it is one of the few elements that exists in more than one stable isotope. There are 24 known isotopes of chromium, but only two of them are stable: chromium-52 and chromium-53. This means that there is a about 50/50 chance that an atom of chromium will be either chromium-52 or chromium-53.
How can you remember the Electronic Configuration of Chromium?
Chromium is a transition metal located in the middle of the periodic table. Transition metals are characterized by their ability to form multiple oxidation states and by their valence electrons being located in d orbitals. The electronic configuration of chromium is 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5. The “superscript” number after each element indicates how many electrons are in that orbital; the “subscript” number after each orbital indicates the energy level of that orbital. So, for chromium, we have 1 electron in the 1s orbital, 2 electrons in the 2s orbital, 6 electrons in the 2p orbitals, etc.
To remember the electronic configuration of chromium, we can use a mnemonic device called Hund’s Rule. Hund’s Rule says that, whenorbitals are unfilled, they will be filled with one electron each before any orbital is filled with two electrons. This rule helps us to remember which orbitals are filled first when we look at an electron configuration. For chromium, we would start by filling the 1s orbital with 1 electron, then fill the 2s and 2p orbitals with 2 electrons each (remembering to follow Hund’s Rule), then fill the 3s and 3p orbitals with 6 electrons each. Finally, we would fill the 4s orbital with 1 electron and fill the 3d orbitals
Conclusion
The electron configuration of chromium is 1s2 2s2 2p6 3s2 3p6 4s1 3d5. This configuration results in chromium having 18 valence electrons, which allows it to form stable bonds with other atoms. Chromium is a transition metal, meaning that it can easily lose or gain electrons to form cations or anions. As a result, chromium is often used in electroplating and as a catalyst in chemical reactions.