# How to Write the Electron Configuration for Niobium (Nb)

Niobium is the 41th element in the periodic table and the symbol is ‘Nb’. Niobium has an atomic number of 41, which means that its atom has 41 electrons around its nucleus. Niobium is an exception to the rules for writing electron configurations.

**To write the electron configuration for niobium, the first two electrons enter the 1s orbital. Since the 1s orbital can hold only two electrons the next two will enter the 2s orbital. The next six electrons enter the 2p subshell. The p subshell can hold a maximum of six electrons. So first we put six electrons in the 2p subshell and then the next two electrons in the 3s orbital.**

**Since the 3s is now full, the electrons will move to the 3p subshell, where the next six electrons will enter. The 3p subshell is now full. Consequently, the following two electrons will enter the 4s orbital. Since the 4s orbital is full, the next ten electrons will move into the 3d subshell.** **The 3d subshell is now full.** **Consequently, the next six electrons will enter the 4p subshell.**

**Since the 4p is full, the next two electrons will move to the 5s orbital. But the values of the 5s and 4d subshell of niobium are almost the same. Due to the fascination of electrons in the nucleus, one electron moves from 5s to 4d subshell. So first we put one electron in the 5s orbital and then the next four electrons enter the 4d subshell. Hence, the electron configuration of niobium will be 1s ^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{6} 5s^{1} 4d^{4}.**

The electron configuration of niobium refers to the arrangement of electrons in the niobium atom’s orbitals. It describes how electrons are distributed among the various atomic orbitals and energy levels, and provides a detailed map of where each electron is likely to be found.

To understand the mechanism of niobium electron configuration, you must understand two basic things. These are orbits and orbitals. Also, you can arrange electrons in those two ways. In this article, I have discussed all the necessary points to understand the mechanism of niobium electron configuration. I hope this will be helpful in your study.

## Electron arrangement of Niobium through Bohr model

Scientist Niels Bohr was the first to give an idea of the atom’s orbit. He provided a model of the atom in 1913 and provided a complete idea of orbit in that model.

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

The name of the first orbit is K, 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 2n^{2}.

Shell Number (n) | Shell Name | Electrons Holding Capacity (2n^{2}) |

1 | K | 2 |

2 | L | 8 |

3 | M | 18 |

4 | N | 32 |

### Explanation:

- Let, n = 1 for K orbit. So, the maximum electron holding capacity in the K orbit is 2n
^{2}= 2 × 1^{2}= 2 electrons. - n = 2, for L orbit. The maximum electron holding capacity in the L orbit is 2n
^{2}= 2 × 2^{2}= 8 electrons. - n=3 for M orbit. The maximum electron holding capacity in the M orbit is 2n
^{2}= 2 × 3^{2 }= 18 electrons. - n=4 for N orbit. The maximum electron holding capacity in N orbit is 2n
^{2}= 2 × 4^{2}= 32 electrons.

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 niobium is 41. That is, the number of electrons in niobium is forty-one. Therefore, a niobium atom will have two electrons in the first shell, eight in the 2nd orbit, and eighteen electrons in the 3rd shell.

According to Bohr’s formula, the fourth shell will have thirteen electrons but the fourth shell of niobium will have twelve electrons and the remaining one electron will be in the fifth shell. Therefore, the order of the number of electrons in each shell of the niobium atom is 2, 8, 18, 12, 1.

## Electron configuration of Niobium 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.

Orbit Number | Value of ‘l’ | Number of subshells | Number of orbitals | Subshell name | Electrons holding capacity | Electron configuration |

1 | 0 | 1 | 1 | 1s | 2 | 1s^{2} |

2 | 0 1 | 2 | 1 3 | 2s 2p | 2 6 | 2s^{2} 2p^{6} |

3 | 0 1 2 | 3 | 1 3 5 | 3s 3p 3d | 2 6 10 | 3s^{2} 3p^{6} 3d^{10} |

4 | 0 1 2 3 | 4 | 1 3 5 7 | 4s 4p 4d 4f | 2 6 10 14 | 4s^{2} 4p^{6} 4d^{10} 4f^{14} |

### Explanation:

- 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.

Sub-shell name | Name source | Value of ‘l’ | Value of ‘m’(0 to ± l) | Number of orbital (2l+1) | Electrons holding capacity2(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 |

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.

Orbital | Orbit (n) | Azimuthal quantum number (l) | Orbital energy (n + l) |

3d | 3 | 2 | 5 |

4s | 4 | 0 | 4 |

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.

Following the Aufbau principle, the sequence of entry of electrons into orbitals is 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p.

Therefore, the complete electron configuration for niobium should be written as 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{6} 5s^{1} 4d^{4}.

Note:The unabbreviated electron configuration of niobium is [Kr] 4d^{4}5s^{1}. When writing an electron configuration, you have to write serially.

## Niobium ion(Nb^{5+}) electron configuration

The ground state electron configuration of niobium is 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 3d^{10} 4s^{2} 4p^{6} 4d^{4} 5s^{1}. This electron configuration shows that the last shell of niobium has an electron and the d-orbital has a total of four electrons. Therefore, the valence electrons of niobium are five.

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.

During the formation of a bond, niobium donates an electron of the last shell and four electrons of the 4d orbital to form bonds and turns into a niobium ion(Nb^{5+}). That is, niobium is a cation element.

Nb – 5e^{–} → Nb^{5+}

The electron configuration of niobium ion(Nb^{5+}) is 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 3d^{10} 4s^{2} 4p^{6}. The electron configuration shows that the niobium ion(Nb^{5+}) has four shells and the last shell has eight electrons. This electron configuration shows that the niobium ion has acquired electron configuration of krypton and it achieves an octave full stable electron configuration.