Francium Electron Configuration: 7 (Easy Step-by-Step Guide)

Francium is the group 1 alkali metal in the periodic table having a molar mass of 223 u. Let us study the electronic configuration of francium in detail.

Fr is an extremely radioactive alkali metal and its one isotope has only 22 mins half-life.  It adopts a body-centered cubic lattice in its crystal form and the first ionization energy of Fr is very low because it gains stability after the removal of one electron. Although it is a metal its melting point is very low.

It can be synthesized by the nuclear fission of the Au with a high amount of energy. Now in this article, we should discuss the electronic configuration of Fr, along with the orbital diagram, electronic notation, ground, and excited state electronic configuration with proper explanation.

1. How to write the Francium electron configuration

Fr is the group 1 and 7th-period element so it has 87 electrons and those electrons should be arranged properly in the electronic configuration by the following steps,

  • Step 1- First of all, we write the shell number according to the principle quantum number in increasing order of them to obey Aufbau’s principle which is the fundamental step of electronic configuration.
  • Due to more than 86 electrons, it was found that Fr has 7 electronic shells.
  • Step 2- After that, we should incorporate the subshell or orbital for each principle quantum number.
  • s, p, d, and f all four orbitals can hold a total of 87 electrons for Fr.
  • Step 3- we put the respective number of electrons in each shell or orbital as per Hund’s rule.
  • Step 4- Now fill the extra electrons in each respective shell by Pauling’s exclusion principle.

2. Francium electron configuration diagram

Fr has 87 electrons and all the electrons should be placed in the respective electronic shell as per the above three principles,

  • First, 1s will be filled by two electrons as it has lower energy and it has one orbital, and each orbital consists maximum of two electrons with opposite spin.
  • After 1s, 2s orbital will be filled by two electrons as per energy order
  • After 2s, the 2p orbital will be filled as per energy order and it has three orbitals so it can accumulate a maximum of six electrons.
  • After 2p, the 3s orbital is filled by two electrons as per higher energy than the previous one.
  • After 3s, the 3p orbital will be filled by six electrons as it has three orbitals and more energy.
  • After 3p, the 4s orbital will be filled by two electrons as it has higher energy for a higher principle quantum number.
  • After 4s, the 3d orbital will be filled due to effective nuclear charge and shielding effect it has higher energy than 4s and the d orbital has five subshells so it can accumulate a maximum of ten electrons.
  • After 3d, the 4p orbital will be filled by six electrons.
  • After 4p, the 5s orbital is filled by two electrons as per energy.
  • After 5s, the 4d orbital is filled by a maximum of ten electrons as it has more energy than 5s.
  • After 4d, the 5p orbital is filled by the six electrons.
  • After 5p, the 6s orbital is filled by two electrons.
  • After 6s, 4f orbital will be filled by a maximum of 14 electrons as f orbital contains seven subshells and due to poor screening effect, it has more energy than the former.
  • After 4f, the 5d orbital will be filled by 10 electrons.
  • After 5d, 6p orbital will be filled by the six electrons.
  • And lastly 7s orbital will be filled by one electron as per the availability of the electron of Fr in the valence shell.
  • So, all the 87 electrons will be filled in the diagram will be –
Screenshot 2022 11 17 152702
Francium Electronic diagram

3. Francium electron configuration notation

The electronic configuration notation of Francium is symbolized as –


This notation contains 87 electrons where Rn has 86 electrons so here we use noble gas configuration and the remaining extra 1 electron. We use the next orbital which is 7s, where 7 is the principle quantum number and s is the orbital.

4. Francium unabbreviated electron configuration

The unabbreviated electronic configuration of Francium is,

1s22s22p63s23p63d104s24p64d10 4f14 5s25p65d106s26p67s1

The Francium unabbreviated electron configuration consists of a total of 87 electrons which are filled as follows –

  • Two electrons are present in 1s orbital.
  • Two electrons in 2s orbital.
  • Six electrons in 2p orbital.
  • Two electrons in 3s orbital.
  • six electrons in 3p orbital.
  • Ten electrons in 3d orbital.
  • Two electrons in 4s orbital.
  • Six electrons in 4p orbital.
  • Ten electrons in 4d orbital.
  • Fourteen electrons in 4f orbital.
  • Two electrons in 5s orbital.
  • Six electrons in 5p orbital.
  • Ten electrons in 5d orbital.
  • Two electrons in 6s orbital.
  • Six electrons in 6p orbital.
  • One electron in 7s orbital.

5. Ground state Francium electron configuration

Fr ground state electronic configuration is, 1s22s22p63s23p63d104s24p64d10 4f14 5s25p65d106s26p67s1.Which is also its unabbreviated form where all the 87 electrons are suitably placed in proper orbital by respective energy order.

Screenshot 2022 11 17 152901
Francium Ground State
Electornic Configuration

6. Excited state of Francium electron configuration

Fr excited state electronic configuration will be, 1s22s22p63s23p63d104s24p64d10 4f14 5s25p65d106s26p57s2. Here one electron from the 6p orbital shifted to the higher energy orbital 7s, and 7s get filled by providing energy. The promotional energy between 6p and 7s is low due to the relativistic effect.

Screenshot 2022 11 17 153015 1
Francium Excited State
Electornic Configuration

7. Ground state Francium orbital diagram

The Francium ground state orbital diagram is the presence of 87 electrons per shell around the nucleus as per quantum number and it needs 7 shells to arrange those 87 electrons and they are,

  • K -shell = containing two electrons (1s1)
  • L-shell = containing 8 electrons (2s22p6)
  • M-shell = containing 18 electrons (3s23p63d10)
  • N-shell = containing 32 electrons (4s24p64d104f14)
  • O-shell = containing 18 electrons(5s25p65d10)
  • P-shell = containing 8 electrons(6s26p6)
  • Q-shell = containing remaining 1 electron(7s1)
  • The orbital diagram of Francium will be-
Screenshot 2022 11 17 153241
Francium Orbital Diagram


Francium is the 7s period element so it shows higher radioactivity and for this reason, it cannot be used in a such chemical reaction. But it can form halide and perchlorate-like lower congeners. It can be used in spectroscopy to determine the coupling constant of a proton.

Read more about Cesium (Cs) Electron Configuration.

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