Question

Mention any three diagonal relationship similarities between Beryllium and Aluminium.

Answer 1

Beryllium is a chemical elements which belongs to ${2^{nd}}$ group period of the periodic table whereas aluminium is a chemical element which is situated in the thirteenth group and the ${3^{rd}}$ period of the periodic table.

Complete step by step answer:
Beryllium $\left( {Be} \right)$ is a chemical element having atomic number $4$. It is an alkali earth metal which is situated in the ${2^{nd}}$ group and ${2^{nd}}$ period of the periodic table. Its atomic mass is $9$ . It is a S - block element with an electronic configuration of $1{s^2}2{s^2}$ .
On the other hand, Aluminium $\left( {Al} \right)$ is a chemical element that has an atomic number $13$. It is a metal which belongs to the boron family and can be located in the thirteen group and ${3^{rd}}$ period of the periodic table. It has an atomic mass of $26$. It is a $p - block$ element and has the electronic configuration as $1{s^2}2{s^2}2{p^6}3{s^2}3{p^1}$ .
However, the beryllium shows resemblance with its diagonally opposite element i.e. Aluminium. Thus, both these elements show some similarities. Firstly, both these metals have the tendency to form covalent compounds e.g. the chlorides of both these atoms are covalent and are soluble in organic solvents. Moreover, their chlorides act as a lewis acid. Their chlorides, $BeC{l_2}$ and $AlC{l_3}$ , have chlorine bridged structures in the vapour phase.
Secondly, both these elements have the same electronegativity and the polarizing power i.e. they have the same change to radius ratio of their ions. Also, due to the same polarizing power, they form the same complexes thirdly, the oxides of both these elements are hard, high melting insoluble solids. Their oxides and hydroxides are amphoteric in nature and dissolve in sodium hydroxide solution as well as in hydrochloric acid.

Note: The carbides of both these elements do react with water to liberate methane gas. The salts of both these elements form hydrated ions in aqueous solution. $BeC{l_2}$and$AlC{l_3}$ both of them are also used as Friedel-Crafts catalysts.