Classification of Elements on the Basis of Electronic Configuration

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Vital idea in chemistry is the grouping of elements according to their electronic configuration, which enables us to understand how the arrangement of electrons in atoms influences the characteristics and behavior of individual elements. This categorisation clarify the element’s chemical reactivity, kinds of bonds they form, and their groupings.

1. Electronic Configuration

Distribution of electrons in an atom’s orbit is referred as electronic configuration. Arrangement stick to a particular order, determined by the Aufbau principle, Pauli exclusion principle, and Hund’s rule in quantum mechanics. As per the Aufbau principle, electrons occupy orbits in ascending order of energy.
Each orbit can only contain a maximum of two electrons with opposing spins, according to the Pauli exclusion principle, and electrons will fill degenerate orbit  singly before pairing, according to Hund’s rule.
Classification of Elements on the Basis of Electronic Configuration-Electrons
Electrons

2. Classification Based on Valence Electrons

Valence electrons (electrons in the outermost shell) of the elements are the main means by which they are grouped and categorised in the periodic table. Element’s chemical characteristics and capacity of elemental bonding are determined by the quantity of valence electrons in that element.

Main categories are:

  • s-block elements:- s orbit is occupied by the outermost electrons. Alkali metals (Group 1) and alkaline earth metals (Group 2) make form the s-block. Alkali metals are extremely reactive, particularly when it comes to water, because they only have one electron in their outermost s orbit. Compared to alkali metals, alkaline earth metals are slightly less reactive due to having two electrons in the outermost s orbit
  • p-block elements:- Consists of Groups 13 through 18, is made up of elements in which the last electron enters any one of the three p orbits. Metals, nonmetals, and metalloids are all included in the p-block. Group 17, for example, consists of halogens, has seven valence electrons, which makes them extremely reactive as they try to acquire an electron in order to form a stable octet configuration. Noble gases, or group 18 elements, are inert because of their stable electronic structure and complete p orbits.
Classification of Elements on the Basis of Electronic Configuration-Stole metal
Stole metal
  • d-block elements:-These elements, also referred as transition metals, have an electron that entered the d orbit. They are in Groups 3–12. Capacity of transition metals are to generate different oxidation states, colorful compounds, and catalytic properties. Because electrons in the last but one shell’s s and d orbits can engage in bonding, the material has special qualities such high melting temperatures, ductility, and the ability to form complex ions.
  • f-block elements:- Actinides and lanthanides that make up the f-block elements whose last electron occupies a f orbit. At the bottom of the periodic chart, they are frequently arranged individually.  Because they fill the 4f orbits, lanthanides are noted for having comparable qualities to actinides, which fill the 5f orbits and are usually radioactive with important uses in nuclear energy and industry.

Note:-

Periodic table offered a thorough knowledge by the classification of elements according to their electrical configuration, and also explain how the elements are arranged and behave chemically. It is an essential means for chemists and scientists researching matter and its properties because it establishes the framework for forecasting how components will interact in chemical reactions.
Element’s chemical properties and behaviors can be aided by classifying it according to its electronic configuration. It enables scientists to forecast the types of bonds that will form between elements, how those elements will respond under various circumstances, and how those elements will interact in chemical reactions
Outermost electrons of s-block elements are found in the s orbit. Periodic table’s Groups 1 and 2 comprise these elements. Group 2 elements, referred  as alkaline earth metals, have two electrons in the s orbit, whereas Group 1 elements, known as alkali metals, only have one electron in the outermost s orbit. Similar chemical characteristics are produced by this configuration, such as modest reactivity in alkaline earth metals and high reactivity in alkali metals.
P-block elements are those that are located in Groups 13 through 18 of the periodic table and have their outermost electrons entering the p orbit. These elements, have different quantities of valence electrons that affect their reactivity and bonding, consist of metals, non-metals, and metalloids. On the other hand, the outermost electrons of d-block elements, commonly referred as transition metals, occupy the d orbit. The elements, which belong to Groups 3 through 12, are well-known for their capacity to function as catalysts, numerous oxidation states, and capacity to generate colorful compounds.
To preserve the periodic table’s organisation and legibility, the f-block elements are arranged independently near the bottom.  Electrons in these elements are actinides and lanthanides fill the f orbit. By arranging them individually, we can prevent the table from growing horizontally, which would have make it complicated. Even, their complicated electron configuration and special characteristics like radioactivity in actinides, f-block elements are often kept as a separate category.
Atomic size and ionisation energy are two examples of periodic patterns that are directly influenced by electronic configuration.  Higher nuclear charge causes electrons to be drawn closer, decreasing the size of the atom. The number of electron shells down a group increases the size of an atom. Because of the increased attraction between the nucleus and electrons, the energy needed to remove an electron, or ionisation energy, often increases over time. As electrons are easier to remove when farther from the nucleus.

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