Which group of elements does not show a diagonal relationship?
 A.$Li,Mg$
 B.$Be,Al$
 C.$B,Si$
 D.$C,P$

Hint: We have to know that, in inclining relationships in S block components exist between adjoining components which are situated in the second and third times of the intermittent table. The properties of S block components shift essentially when contrasted with different components of the sub-bunch they have a place with.

Complete answer:
We have to know that the above points,
The corner to corner neighbors show a ton of similitudes. Such a relationship is displayed as you move left to right and down the gathering; the occasional table has contradicting factors.
A few connections happen due to the various manners by which numerous nuclear properties shift down gatherings and across times of the Periodic Table.
Notwithstanding the gathering and period connections, the components of s and p-block components likewise show corner to corner connections.
On moving corner to corner across the occasional table, the components show certain likenesses which are anyway undeniably less articulated than the similitudes inside a gathering. The corner to corner relationship is especially perceptible in the components of the second and third times of the intermittent table.

Therefore, the diagonal relationships are $Li,Mg$ , $Be,Al$ , $B,Si$ .
Hence, $C,P$ group of elements does not show a diagonal relationship.

The correct option is (D).

Note:
We have to know that the diagonal relationship is formed due to the identical size of ions. As we move towards the right across a period in the periodic table, then the size of the atom reduces, and when we move downward across a group then the size of the atoms gradually increases.