Electronic Configuration of s-Block Elements in The Modern Periodic Table

Group 1 and Group 2 elements of the modern periodic table are the s-block elements. Group 1 elements are called as alkali metals and Group 2 elements are called as alkaline earth metals due to the reactivity of these elements. The electronic configuration of alkali and alkaline earth metals is explained below.

In the term ‘electronic configuration’ the word electronic means electrons and configuration mean the arrangement of parts. The electronic configuration is the arrangement of electrons in the orbitals. The rules for drawing the electron diagram of elements remain the same. The lowest energy level should be filled with electrons first and then the higher energy levels should be filled as per Aufbau’s principle. During the filling of electrons Aufbau’s principle, Hund’s rule and Pauli’s exclusion principle should be taken into consideration. Hund’s rule states that in a subshell every orbital is first singly occupied and then double occupancy is possible and all the electrons which are singly occupied have the same spin. Pauli’s exclusion principle states that no two electrons can have the same quantum number (n, l, m, s).The atomic orbital diagonal rule is as shown below:


Electronic configuration of Alkali metals:

The alkali metals consist of a single valence electron in their outermost shell. This outermost electron is loosely held which makes these metals highly electropositive. Due to which they are not available in the free state in nature. The general electronic configurations of group 1 metals are as shown in the table below:



Element Symbol Electronic configuration
Lithium Li 1s22s1
Sodium Na 1s22s22p63s1
Potassium K 1s22s22p63s23p64s1
Rubidium Rb 1s22s22p63s23p63d104s24p65s1
Caesium Cs [Xe]6s1
Francium Fr [Rn]7s1


Electronic configuration of alkaline earth metals:

Elements Symbols Electronic configuration
Beryllium Be [He]2s2
Magnesium Mg [Ne]3s2
Calcium Ca [Ar]4s2
Strontium Sr [Kr]5s2
Barium Ba [Xe]6s2
Radium Ra [Rn]7s2


The electronic configuration of the S-block elements explained is a brief study. To know more regarding this topic or to clear doubts to get in touch with the Byju’s mentor team

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