The Electronic Configuration

Before allocating an atom’s electrons to orbitals, one must first understand the fundamental ideas of the electron configurations. Atoms, which are made up of protons, neutrons , and electrons, make up every element on the Periodic Table. The four types of orbitals (s,p,d, and f) have various forms, and each orbital can only house two electrons at a time. Because the sublevels of the p, d, and f orbitals differ, they can carry more electrons.

Rules for Assigning Electron Orbitals –

Occupation of orbitals

Electrons fill orbitals in such a way that the atom’s energy is minimized. As a result, electrons in an atom fill the primary energy levels in an ascending sequence of energy ( the electrons are getting farther from the nucleus). The following is the order in which the levels were filled:

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 7s, 5f, 6d, 7p, 7s, 5f, 6d, 7p

One of the simplest ways to recall this pattern is to look up the periodic table and remember where each other orbital block belongs  to logically determine the pattern. Another option is to use vertical lines to determine which subshells belong to each in a table like the one below.

Pauli Exclusion Principle-

No two electrons may have the same four quantum numbers, according to the Pauli exclusion principle. The first three quantum numbers(n, l, and ml) can all be the same, but the fourth must be different.

Hund’s principle-

Before partnering with another electron in a half-filled orbital, each electron will first fill all of the orbitals with similar energy ( also known as degenerate).

The Aufbau process

The word “aufbau” derives from the German word “ aufbauen”, which means to construct. Orbitals are built up from atom to atom while writing electron configurations. Orbitals are built up from atom to atom while writing electronic configurations. Orbitals are filled in order of increasing atomic number when writing an atom’s electron configuration.

Writing Electronic Configuration

Write the energy level ( the period ) first, then the subshell to be filled , and finally the superscript, which is the number of electrons in that subshell. The atomic number, Z, represents the total amount of electrons. The electronic configurations for all of the elements in the periodic table can be written using the rules above. Electron configurations are written using this methods:

1. s p d f notation for orbital diagrams noble gas notation.
2. Each method serves a distinct function and has its own set of disadvantages.

Orbital diagrams

It is a visual representation of the electronic configuration  that shows each of the individual orbitals as well as the electron spinnings.This is accomplished by first determining the subshell ( s, p,d or f) and then drawing in each electron using the above- mentioned principles.

s p d f notation

The spdf notation is the most commonly used notation for describing electron configurations. The total number of electrons in each energy level is described by a superscript that follows the corresponding energy level, even if the distributions of electrons in each orbital are not as obvious.

Noble gas notation

This raises an important topic about electronic configurations and elements. When the p subshell in the previous example regarding the Aufbau principle ( the trend from boron to neon) is full, it reaches the noble gas group. Noble gasses are noted for having the most stable electron configurations and for being generally inert. Because all noble gasses have filled subshells, they can be utilized to write electron configurations for future atoms in a shorthand manner. The noble gas notation is a method of writing configurations in which the noble gas in the period above the element being analyzed is used to denote the subshells that element has filled and then the valence electrons are used to denote the valence electrons.

Why are Electronic Configurations Important?

By assisting in the determination of an atom’s valence electrons , electron configurations provide proper insight into the chemical and physical properties of elements. It also aids in the classification of elements into separate ( such as the s-block elements, the p-block elements, the d- block elements, and the f- block elements). This makes it easy to investigate the properties of the components as a group.

Applications  of Electronic Configuration

The interpretation of atomic spectra is a key application of electron configurations. In this situation, one or more term symbols that describe the various energy levels available to an atom must be added to the electron configuration. Although not all of the energy levels are observed in practice, term symbols can be derived for any electron configuration, not simply the ground state configuration 

Conclusion

So we came to know that electronic configurations can be used to determine an element’s valency. Predicting a group of elements qualities the interpretation of atomic spectra. Understanding the structure of the periodic table of elements requires knowledge of the electronic configuration of various atoms. This is also a good way to talk about the chemical bonds that hold atoms together . This similar concept can be used to explain the unusual features of lasers and semiconductors in bulk materials.