The Diagonal Relationship between Group 1 and 2 Elements on The Periodic Table

Introduction

Diagonal relationship refers to the resemblance in attributes between two elements that are diagonally adjacent in the second and third period of the periodic table.

Beryllium is the first element in Group 2 of the s-block elements, while Lithium is the first element in Group 1.

Other components in their group have attributes that don’t match up with their own.

Because of the similarities in ionic sizes and radius ratio of the elements, their properties reflect those of the second element in the following group.

As a result, lithium and magnesium share comparable qualities, whereas Beryllium and Aluminium do.

Group 1 and Group 2 Elements Form a Diagonal Relationship

In the second and third periods of the periodic table, there is a diagonal link between some pairs of diagonally adjacent elements that can be seen. Be and Al, Li and Mg, B and Si and so on have the same properties. There are many examples of semiconductors that have acidic oxides, which hydrolyze into halides in water, such silicon and boron. Because of the descending and crossing effects of the periodic table, this relationship is formed between the two elements.

The size of an atom decreases when it crosses a period of the periodic table, while the size of an atom increases when it descends a group in the periodic table. The elements become more covalent, more electronegative, and less reducing as they advance through the periods. As you move down the periodic table, the elements become less electronegative, more ionic, and more basic as you go. As a result, elements with comparable chemistry and characteristics are frequently encountered when a group is crossed or descended by a single element. Compound properties, electronegativity, and the diagonal members’ atomic size are all comparable.

First- and second-group elements share a chemistry that is well-known in the scientific community. As a result, lithium’s chemistry is quite similar to that of magnesium’s. In terms of chemistry, beryllium and boron share many similarities with aluminium, while silicon is comparable to boron. What you’re seeing here is known as a “diagonal relation.” Aside from that, it’s barely perceptible. Diagonal relationships are still not entirely understood, but they are affected by the charge density. For example, lithium has a +1 charge and magnesium has a +2 charge, but the charge density on each ion is nearly the same.

Under normal conditions of temperature and pressure, the lithium-magnesium couple illustrates the diagonal relationship nicely.

• Only oxides are created by lithium and magnesium under ordinary conditions, while sodium produces peroxides. Aside from that, the super-oxides are formed by metals lower than sodium.
• The stable nitride Li3N can only be formed by lithium in group I. The nitrides are formed by magnesium and other elements of group II.
• The group II salts of lithium carbonate, fluoride, and phosphate are water-insoluble to varying degrees.
• The covalent organometallic compounds are made up of lithium and magnesium. The synthetic reagents MgMe2 and LiMe are both very useful. This makes it harder to work with the other counterparts of group I and group II.
• lithium and magnesium chlorides are both soluble in pyridine and alcohol, which causes them to deliquesce. Hydrated crystal LiCl2H2O of lithium chloride is isolated from the lithium chloride.
• It’s the ability to establish covalent bonds with elements of average electronegativity that sets lithium and magnesium apart from other metals.

Diagonal relationship

The periodic table is considered to have a diagonal link between some pairs of neighbouring elements in the second and third period (the first 20 elements). They have similar features, such as boron and silicon producing halides that hydrolyze in water and have acidic oxides when boron is hydrolyzed with water and silicon when boron is hydrolyzed with water.

Certain connections are made more obvious by the periodic table’s arrangement of elements in horizontal rows and vertical columns (periodic law). Atomic radii of isolated atoms are affected in opposite ways by moving to the right and descending the periodic table, respectively. The atomic radii of atoms decreases as the period is crossed to the right, whereas the atomic radii increases as the period is crossed to the left. 

Element properties change in the opposite direction when travelling up or down a period: advancing to the right results in elements becoming increasingly covalent[clarification needed], less basic, and more electronegative. The changes “cancel” each other out when a period is descended or when a group is crossed by one element, so elements with similar properties that share the same chemistry are frequently found. This is especially true for the diagonal members, whose atomic size, electronegativity, compound properties, and so on are similar.

Period 2 elements often have chemistry that resembles that of period 3 elements one column to their right in the periodic table, according to research. This means that the chemistry of Li is similar to that of Mg, Be similar to that of Al, and B similar to that of Si. These correlations are known as diagonals. It is less noticeable after B and Si.

Conclusion

From the following article we can conclude that Diagonal relationship refers to the resemblance in attributes between two elements that are diagonally adjacent in the second and third period of the periodic table. Beryllium is the first element in Group 2 of the s-block elements, while Lithium is the first element in Group 1.