Electron Configuration for Potassium (K, K+ ion) (2024)

Potassium is the 19th element in the periodic table and its symbol is ‘K’. In this article, I have discussed in detail how to easily write the complete electron configuration of potassium.

I also discussed how to draw and write an orbital diagram of potassium. Hopefully, after reading this article, you will know more about this topic.

What is the electron configuration of potassium?

The total number ofelectrons in potassiumis nineteen. These electrons are arranged according to specific rules in different orbitals.

The arrangement of electrons in potassium in specific rules in different orbits and orbitals is called the electron configuration of potassium.

The electron configuration of potassium is [Ar] 4s¹,if the electron arrangement is through orbitals. Electron configuration can be done in two ways.

• Electron configuration through orbit(Bohr principle)
• Electron configuration through orbital(Aufbau principle)

Electron configuration through orbitals follows different principles. For example Aufbau principle, Hund’s principle, and Pauli’s exclusion principle.

Electron configuration of potassium through orbit

Scientist Niels Bohr was the first to give an idea of the atom’s orbit. He provided a model of the atom in 1913. The complete idea of the orbit is given there.

The electrons of the atom revolve around the nucleus in a certain circular path. These circular paths are called orbit(shell). These orbits are expressed by n. [n = 1,2,3,4 . . . The serial number of the orbit]

K is the name of the first orbit, L is the second, M is the third, and N is the name of the fourth orbit. The electron holding capacity of each orbit is 2n².

For example,

1. n = 1 for K orbit.
   The maximum electron holding capacity in K orbit is 2n²= 2 × 1²= 2.
2. For L orbit, n = 2.
   The maximum electron holding capacity in L orbit is 2n²= 2 × 2²= 8.
3. n=3 for M orbit.
   The maximum electrons holding capacity in M orbit is 2n²= 2 × 3²= 18.
4. n=4 for N orbit.
   The maximum electrons holding capacity in N orbit is 2n²= 2 × 4²= 32.

Therefore, the maximum electron holding capacity in the first shell is two, the second shell is eight and the 3rd shell can have a maximum of eighteen electrons. The atomic number is the number of electrons in that element.

The atomic number of potassium is 19. That is, the number of electrons in potassium is nineteen. Therefore, the potassium atom will have two electrons in the first shell and eight in the 2nd shell.

According to Bohr’s formula, the third orbit will have nine electrons but the third orbit of potassium will have eight electrons and the remaining one electron will be in the fourth orbit.

Therefore, the order of the number of electrons in each shell of the potassium(K) atom is 2, 8, 8, 1. Electrons can be arranged correctly through orbits from elements 1 to 18.

The electron configuration of an element with an atomic number greater than 18 cannot be properly determined according to the Bohr atomic model. The electron configuration of all the elements can be done through orbital diagrams.

Electron configuration of potassium through orbital

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

For example,

• If n = 1,
  (n – 1) = (1–1) = 0
  Therefore, the value of ‘l’ is 0. So, the sub-energy level is 1s.
• If n = 2,
  (n – 1) = (2–1) = 1.
  Therefore, the value of ‘l’ is 0, 1. So, the sub-energy levels are 2s, and 2p.
• If n = 3,
  (n – 1) = (3–1) = 2.
  Therefore, the value of ‘l’ is 0, 1, 2. So, the sub-energy levels are 3s, 3p, and 3d.
• If n = 4,
  (n – 1) = (4–1) = 3
  Therefore, the value of ‘l’ is 0, 1, 2, 3. So, the sub-energy levels are 4s, 4p, 4d, and 4f.
• If n = 5,
  (n – 1) = (n – 5) = 4.

Therefore, l = 0,1,2,3,4. The number of sub-shells will be 5 but 4s, 4p, 4d, and 4f in these four subshells it is possible to arrange the electrons of all the elements of the periodic table.

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.

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.

Aufbau is a German word, which means building up. The main proponents of this principle are scientists Niels Bohr and Pauli. The Aufbau method is to do electron configuration through the sub-energy level.

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.

The energy of an orbital is calculated from the value of the principal quantum number ‘n’ and the azimuthal quantum number ‘l’. The orbital for which the value of (n + l) is lower is the low energy orbital and the electron will enter that orbital first.

Here, the energy of 4s orbital is less than that of 3d. So, the electron will enter the 4s orbital first and enter the 3d orbital when the 4s orbital is full.

The method of entering electrons into orbitals through the Aufbau principle is 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d.

The first two electrons of potassium enter the 1s orbital. The s-orbital can have a maximum of two electrons. Therefore, the next two electrons enter the 2s orbital. The p-orbital can have a maximum of six electrons.

So, the next six electrons enter the 2p orbital. The second orbit is now full. So, the remaining electrons will enter the third orbit. Then two electrons will enter the 3s orbital of the third orbit and the next six electrons will be in the 3p orbital.

The 3p orbital is now full. So, the remaining one electron will enter the 4s orbital. Therefore, the potassium full electron configuration will be 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹.

Note:The unabbreviated electron configuration of potassium is [Ar] 4s¹. When writing an electron configuration, you have to write serially.

Video for Potassium Electron Configuration

Electron configuration of potassium in the excited state

Atoms can jump from one orbital to another orbital in the excited state. This is called quantum jump.

The ground state electron configuration of potassium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. This electron configuration shows that the last shell of the potassium atom has an unpaired electron. So the valency of potassium is 1.

When potassium atoms are excited, then potassium atoms absorb energy. As a result, an electron in the 3p orbital jumps to the 4s orbital. We already know that the p-subshell has three orbitals.

The orbitals are p_x, p_y, and p_zand each orbital can have a maximum of two electrons. Therefore, the electron configuration of potassium(K*) in an excited state will be 1s² 2s² 2p⁶ 3s² 3p_x² 3p_y² 3p_z¹ 4s².

The valency of the element is determined by electron configuration in the excited state. Here, potassium has an unpaired electron. In this case, also the valency is 1.

Potassium ion(K⁺) electron configuration

After arranging the electrons, it is seen that the last shell of the potassium atom has an electron. Therefore, the valence electrons of potassium are one. The elements that have 1, 2, or 3 electrons in the last shell donate the electrons in the last shell during bond formation.

The elements that form bonds by donating electrons are called cations. Potassium donates the electron of the last shell to form bonds and turns into a potassium ion(K⁺). That is, potassium is a cation element.

K – e^– → K⁺

The electron configuration of potassium ion(K⁺) is 1s² 2s² 2p⁶ 3s² 3p⁶. This electron configuration shows that the potassium ion has three shells and the last shell has eight electrons.

The electron configuration shows that the potassium atom has acquired the electron configuration of argon and it achieves a stable electron configuration.

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