Question

State whether true or false: ‘Be and Al do not show a diagonal relationship’
A. True
B. False

Answer 1

Hint: Think about what the diagonal relationship is and how only the elements in the second and the third period show the diagonal relationship. Identify the periods and groups of the given elements and determine whether they can show a diagonal relationship or not.
Complete step by step answer:
A diagonal relationship is seen in the diagonally adjacent elements of the second and third period that are known to have similar physical and chemical properties. The element from the second period is present in a group that precedes the group the element that is in the third period is present in. So, if the element in the second period is present in the group ‘n’, then the element in the third period is present in the group ‘n+1’. Some examples of elements that show a diagonal relationship are, lithium and magnesium, boron and silicon.
Now, let us look at the given elements, beryllium and aluminium. Beryllium is present in the second period of the periodic table and aluminum is present in the third. So, this satisfies one of the conditions that are required for the elements to be in a diagonal relationship. Let us look at the groups, Beryllium is present in the second group (2A) of the periodic table and aluminium is present in the third (3A). Both the second and the third period do not contain the d-block elements, so if we condense the d-block part, these elements are diagonally adjacent to each other. So, we can say that they satisfy all the conditions.
According to this, we can say that the given statement ‘Be and Al do not show a diagonal relationship’ is false. Hence, the correct answer is ‘B. False’
Additional Information: Some similar properties of Beryllium and Aluminium are:
- Tendency to form covalent compounds
- Chlorides act as Lewis acids
- Same electronegativity
- Resistant to action of acids due to formation of protective oxide layer
Note: While looking at the periodic table, at first glance, it may not seem as though the elements are in a diagonal relationship since they are separated by the d-block elements. But remember that the periods 2 and 3 do not contain d-block elements. So, we can condense that part of the periodic table, like we condense the f-block elements, to say that beryllium and aluminium are diagonally adjacent.