Question

plz someone help me with this question ​

Answer 1

Decreasing order of covalent character -

BeCl₂ > MgCl₂ > CaCl₂ > SrCl₂ > BaCl₂

The ability of a cation to distort the electron cloud of anion is known as polarising power and the tendency of an anion to become polarised by the cation is known as polarisibility.

• Smaller the size of cation, higher the polarising power. Hence, higher the covalent character.

• Larger the size of anion, higher it will be polarised. Hence, higher the covalent character.

Now, in the given question, anion is the same but cation is different. So, the covalent character will depends on polarising power of cation.

Down the group, size of cation increases and electron density decreases. This will decrease the polarising power. Therefore, Be has the highest polarising power in its group and Ba has the lowest polarising power in its group.