Question

Write a note on the diagonal relationship between Be and Al. 

OR 

What are the similarities between beryllium and aluminium?

Answer 1

i. Beryllium is placed in the group 2 and period 2 of the modem periodic table. It resembles aluminium which is placed in group 13 and period 3.

ii. Due to nearly same charge to radius ratio of their ions, beryllium \((\frac{3}{53.55}\) = 0.056) exhibit diagonal relationship.

iii. Due to diagonal relationship, Be and Al show following similarities in their properties: a. Nature of bonding: Both Be and Al have tendency to form covalent chlorides.

e.g.

b. Lewis acids: BeCl₂ and AlCl₃ act as Lewis acids. 

c. Solubility in organic solvents: BeCl₂ and AlCl₃ are soluble in organic solvents. 

d. Nature of oxide: Both Be and Al form amphoteric oxides.