Question

Diagonal relationship is shown between:
A. C and N
B. B and Mg
C. B and Si
D. Be and Al

Answer 1

Hint: Diagonal relationship is shown by the elements of period 2nd and period 3rd which are diagonally placed with each other. These elements show similar properties. In the given options two options are correct.

Complete step by step answer:
Diagonal relationship is shown by the elements which belong to the second period and elements which belong to the third period in the periodic table. The adjacently present element of the second period and third period show similar characteristics, therefore it is said that they possess diagonal relationship.
The elements present in period 2nd are shown below.

2nd group-	Li	Be	B	C	N	O	F	Ne
3rd group	Na	Mg	Al	Si	P	S	Cl	Ar

Here lithium is in diagonal relationship with magnesium, beryllium is in diagonal relationship with aluminum, boron is in diagonal relationship with silicon, carbon is in diagonal relationship between phosphorous, nitrogen is in diagonal relationship with Sulphur, oxygen is in diagonal relationship with chlorine and fluorine is in diagonal relationship between argon.
From the given option, carbon and nitrogen are present adjacent to each other therefore will not show diagonal relationship. Boron and magnesium are not diagonally with each other and will not show diagonal relationship. Boron and silicon are present diagonally to each other and show diagonal relationship. Beryllium and aluminium are present diagonally to each other and thus possess diagonal relationship.
Therefore, the correct option is C and D.

Note:
The diagonal relationship is only applicable to the first 20 elements. Boron and silicon both are semiconductor. Boron and magnesium are present diagonal to each other but oppositely diagonal.