Diagonal relationships within the IA (Lithium) and IIA (Magnesium), IIA (Beryllium) and IIIA (Aluminium) elements in the periodic element show the similarities in the structural properties. The main reason for the diagonal relationship is the same polarising power and equal ionic potential within the elements. The study describes the functional properties of the s-block element and the cause of the diagonal relationship within the periodic table. The single electron in the s-orbital of the alkali metal shows high electropositive properties.

What are s-Block Elements?

Generally, elements in group 1 and group 2 in the periodic table are called S-block elements. s- Block consists of 14 elements in the periodic table including hydrogen, lithium, magnesium, beryllium, boron, aluminium etc. The s-block elements that have one electron in the s-block orbit are called alkali metals. The S-block elements having two electrons in the s-orbit are defined as the alkali earth metals. The elements in the periodic table which have the last valence electron in the s-orbit are called S-block elements. 

Characteristics of S-Block Element

• S-block elements are highly electropositive and they are ready to release a free electron from the S-orbit
• S block elements are soft metal and the number of electrons in the s orbit define their metal properties
• S block elements are defined as the reducing agent and the elements are situated to the left of the periodic table.
• S block elements have low boiling and melting point and are highly reactive 
• The alkali metals of the S-block element show monovalency while the alkaline earth metals have the covalency property.

Cause of Diagonal Relationship in S Block Elements Having These Properties

The primary cause of the relationship is to create covalent bonds within the elements and have the same ionizing potential. The equal polarizing power of the elements is the main reason for showing the same properties of the diagonal elements. The hardness of the compounds in the diagonal position is different from the other elements in the periodic table.

What is the Definition of a Diagonal Relationship?

Diagonal relationships are defined as the same properties within the elements of group 1 and group 2 that have equal ionizing potential. These elements always occur in the combined state due to the same boiling and melting point. The highly negative electrode potential of the elements impacted on the characteristics of the s- block element. A diagonal relationship mainly occurs between the adjacent elements in group 1 and group 2. Diagonal relationship within the elements also helps to form Carbon Phosphorus and Nitrogen Sulphur along with the extended relationship between Li-Mg and Be-Al.

Importance of Diagonal Relationship

Diagonal relationships within the S-block elements have been used in the oxidation and the semiconductor property. The elements are more covalent and due to this, they are electronegative. The diagonal relationship within the laments creates charge density for the covalent bonding. Li and magnesium can form normal oxide whereas Na can form peroxide. The group 1 element can form stable nitride with the help of the group 2 elements in the periodic table. Group 1 and group 2 elements can form covalent bonds easily to create organometallic compounds. Lithium carbonate and magnesium carbonate can produce oxide and are most unstable.

The Main Reason for the Diagonal Relationship

The main reason for the diagonal relationship of the S- block lament is the same ionic potential and equal polarizing power for the formation of covalent bonds. S- Block elements in the periodic table have low boiling and melting point and due to the free electrons in the orbit, they are highly reactive in nature. Polarizing power of the material is defined by the below equation:

Ionic charge/ ionic radius

For example, a lithium compound has a +1 cation and a magnesium ion has a +2 cation, therefore the ionic potential of the lithium and magnesium are the same.

Conclusion

The above study indicates that the group 1 and group elements in the periodic table have the same properties due to the equal polarizing power and low ionizing potential. Free electrons in the s- orbit easily release the electrons for creating a covalent bond. S- Block elements are reducing agents due to the electropositive property and low ionizing potential. Alkali earth metal has the storing electropositive property than an alkali metal.