Lithium shows diagonal relationship with which element?

Diagonal relationship in periodic table:

• A diagonal relationship exists between the pairs of elements in the second and third periods of the periodic table, which are diagonally adjacent.
• When we move downward across a group in the periodic table then the size of the atoms increases gradually but it decreases when we move right across a period in the periodic table.
• Hence, in the second and third periodic table, the elements have comparatively identical sizes of ions which forms the diagonal relationship between them.

The element with which Lithium shows the diagonal relationship:

• Lithium shows a diagonal relationship with Magnesium.
• The small size of Lithium differs from other alkali metals but resembles more with Magnesium.

Hence, Lithium shows a diagonal relationship with the element: Magnesium.