Electronic Configuration

The positions of the electrons around a nucleus are summarised by electron configurations. Each neutral atom has the same number of protons as it does electrons, as we discovered before. Now we’ll arrange those electrons around the nucleus in a pattern that shows their energy as well as the shape of the orbital in which they’re positioned.  Based on what is known about quantum numbers and the figure above, a s orbital requires 2 electrons, a p orbital requires 6 electrons, a d orbital requires 10 electrons, and a f orbital requires 14 electrons. However, we haven’t talked about how these orbitals are filled in the sequence that they are filled. The energy order determines the sequence in which electrons are placed into orbitals. The Aufbau principle is what this is known as. The orbitals with the lowest energy fill first.

All the group elements have the same arrangement and are similar

Remember that Mendeleev grouped elements with the most comparable properties together in the periodic chart. In the periodic table, a group is a vertical column. There is only one valence electron in the 1A elements. This is what allows these elements to behave similarly to the rest of the family. The elements in 1A all are highly reactive, forming compounds in similar proportions and with similar characteristics. Mendeleev classified these elements into the same group based on their chemical properties. The alkali metals are a subgroup of Group 1A. These metals are actually soft and it can be easily cut, despite the fact that other metals are relatively hard.

The alkaline earth metals belong to Group 2A. These elements have comparable properties due to their similar electron structures. The periodic table’s other groups follow the same arrangement. Remember that Mendeleev organised the periodic table such that elements with the most comparable properties were grouped together.

It’s crucial to know the names of a number of additional significant periodic table groupings. Halogens are elements of Group 7A (or 17). This category contains nonmetal elements that are extremely reactive.

The noble gases are classified as part of Group 8A. These elements share a number of characteristics, the most important of which is that they are extremely inactive, rarely forming compounds. When we talk about how compounds develop, we’ll learn why. At room temperature, all of the elements in this category are gases.

Importance of valence shell and valence electrons

The valence shell is the outermost shell of any atom. Any atom’s valence electron can break away from the parent atom and become a free electron if it receives enough energy from an outside influence.

The electrons in an atom’s outermost energy level — the one farthest away from the nucleus — are known as valence electrons. Chemists are interested in the transfer or exchange of electrons when they research chemical reactions.

In order to understand the significance of the valence shell and valence electron, we must first examine the atom’s structure.

We won’t be able to identify the atom’s structure if the valence shell isn’t provided. The valence shell is where all chemical reactions take place. There will be no chemical reaction if this does not happen.

The valence shell and valence electron, once again, give the atom a distinct shape. The valence shell and valence electron also demonstrate all chemical activity.

The reason for stability due to half filled or fully filled orbitals

The elements of the p-block are arranged in groups of 13 to 18 on the periodic table’s right side. The separating electron in the valence p subshell of p-block elements enters the iotas. The n p subshell is gradually filled in these elements in this manner. The electronic valence shell setup of group fifteen elements is ns2 np1-6. Helium has a 1s2 electrical structure. Despite the fact that helium lacks p orbitals, it is classified as a p-block element since its physical and chemical properties are similar to those of the other p-block elements in the eighteenth group. Non-metals make up the majority of p-block elements, with metalloids and metals making up the remainder.

1. Electrons are distributed in a symmetrical manner.

The fact that symmetry promotes stability is well established (as we can consider why oil forms spherical shape when added into water).

The symmetrical distribution of electrons in the completely filled or half-filled subshells makes them stable. As a result, their mutual shielding is limited, and they are strongly drawn to the nucleus.

2. Energy exchange

When two or more electrons with about the same spin are in a degenerate orbital, the stabilising effect is used. The energy released as a result of this exchange is known as exchange energy. When the subshell is half-full or totally filled, the number of exchanges that can take place is at its peak.

To summarise, stability is a result of I) low shielding, II) low coulombic repulsion, and III) higher exchange energy.

Conclusion 

Electron configurations are a quick and easy way to write down all of the electrons in an atom. Positively charged protons in an atom’s nucleus attract negatively charged electrons, as we all know. Because of their attraction to the protons, these electrons all stick together within the atom, but they also repel each other, leading them to spread out in predictable patterns around the nucleus. This produces different geometric shapes known as orbitals, which depict the unique zones around the nucleus that each electron draws out. For each electron in an atom, the orbitals provide recognisable “addresses.”