Chemical Bonding: Ionic Bond

Chemical Bonding: Ionic Bond : To get a good idea about chemicals, you need to know the details of chemical bonding or chemical bond. Chemical bonding is a discussion of how multiple elements or compounds combine to form new compounds. Chemical bonds can exist not only between elements or compounds but also between ions. It is not possible to form any chemical substance without chemical bonding.

Chemical Bonding: Ionic Bond

It is divided into two parts depending on how strong or lasting the chemical bond is. One is the primary bond and the other is the secondary bond. Primary bonds are strong bonds and secondary bonds are relatively weak bonds. Among the primary bonds, we find the three main and known chemical bonds ionic bonds, covalent bonds, and metallic bonds; Examples of secondary bonds are dipole-dipole attraction and hydrogen bonding.

[ Chemical Bonding: Ionic Bond ]

Although all chemical bonds can be described by quantum theory, bonds are described by the principle of stability of the orbits of elements and bonds by VSEPR theory (Valence shell electron pair repulsion) and this is the most common and well known.

VSEPR theory is the theory of the repulsion of the electron pair at the last energy level or valence level of the elements. To explain this, we need to talk about orbits and orbitals.

One of the elements in the periodic table is, let’s say sodium (Na). Sodium has 11 electrons, and its atomic number is 11. The total number of protons in the nucleus of an element is called the atomic number of that element. Protons are charged positively (+) and electrons are charged negatively (-). Although the nucleus in the center of the atom contains a particle called a neutron, the neutron has no charge. The number of electrons and protons inside an atom is always the same so that an atom cannot display a charge and show a neutral charge.

If atoms with different neutrons of the same element are found, they are called isotopes of that element. This unequal neutron does not change the charge or bond of the atom.

However, we will try to understand the chemical bond by explaining their compound structure with another element; let us take Cl with Na. Sodium chloride (NaCl) is a compound formed by sodium (Na-11) and another element chlorine (Cl-17), which is known to all of us as edible salt. And the name of this bond is Ionic Bond. To explain ionic bonds, it is important to understand inert elements, also known as inert gases or noble gases.

Before that let’s take an idea about ionic bonding from the figure below. It turns out that the first energy level of Na has two electrons, the second energy level has eight electrons and the last energy level has one electron. In the case of Cl, the first energy level has two electrons, the second energy level has eight electrons and the last energy level has seven electrons in total.

It is worth mentioning that the electrons revolve around the nucleus of the elements and it is known as orbit or energy level. During the formation of a bond, only electrons are exchanged or given and received between the last energy level. In the case of ionic bonds, electrons are exchanged, but in the case of covalent bonds, electron share occurs, even at the latest energy level.


Let’s get back to the picture. As can be seen from the beginning in the figure above, Na is passing an electron from its last energy level to the last energy level of chlorine. The question is why?
And why is Cl taking an electron? Why isn’t Cl giving seven electrons to Na?

As can be seen, Na has become Na+ by donating an electron and Cl has formed a Cl ion with that one electron. These two single but opposite charge ions attract each other and combine to form a sodium chloride (NaCl) compound. The process of forming a bond by donating and receiving electrons in this way is called an ionic bond because here the bond is formed between two ions and they have become ions by donating and receiving electrons.

Now come back to the questions. To get the answer to the questions, you have to look at the two marked figures 1 and 2 below.

Figure: 1





Figure: 2

The first figure shows the electron configuration of inert gases / Noble gases. Since helium has only two electrons, it has two electrons in its last energy level or two electrons in its only energy level and thus it is stable. That is, He will not react easily. Each subsequent element has eight electrons in the last orbit. These are all stable elements and thus keeping eight electrons in the last orbit to be stable is called Octate Rule.

Figure 2 shows the position of the inert elements/ Noble gas in the periodic table and shows that all the Nobel gas are located in group-18 of the periodic table, there is a total of 18 pillar-like groups in the periodic table.
Interestingly, all the elements of the periodic table want to stabilize by going through the electron configuration of the last energy level of Nobel gas, either by donating or sharing their electrons. The last energy level of Na+ and Cl- has s2 P6 size which is like Ne in the case of Na and Ar as for Cl.

In this case, there is an inert element near any element in the periodic table,
The element wants to be like its nearest inert gas electron configuration when it comes to compound formation. Another explanation is that it is easier to donate or receive fewer electrons.

More details about ionic bonds will be written further in ChemicalGOLN. You can read the next article in ChemicalGOLN about the covalent bond. In addition, the article: “electron configuration” on will be helpful for explanations regarding electron configuration in this article.

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