Question

The correct sequence of increasing covalent characters is represented by?

${\mathrm{LiCl}}_2,\mathrm{NaCl},{\mathrm{BeCl}}_2$

Answer 1

Covalent Character:

• Covalent character is the measure of the tendency of an atom to attract the shared pair of electrons towards itself.
• Let us consider $\mathrm{M}=\mathrm{Na}/\mathrm{Li}/\mathrm{Be}$ and $\mathrm{X}=\mathrm{Cl}$
• The degree of covalent character in a bond between two atoms $\mathrm{M}$ and $\mathrm{X}$ depends on the difference in electronegativity i.e., $∆\mathrm{EN}$.
• When $∆\mathrm{EN}$ is small, the bond has a lot covalent nature.
• If $∆\mathrm{EN}$ is significant, the bond will have little covalent nature.
• In a periodic table, electronegativity increases from top to bottom and from left to right.
• Be is closest to the right and Na is closest to the bottom. Electronegativities rise in the sequence $\mathrm{Na}<\mathrm{Li}<\mathrm{Be}$, whereas they fall in the order:

$\mathrm{Na}-\mathrm{Cl}>\mathrm{Li}-\mathrm{Cl}>\mathrm{Be}-{\mathrm{Cl}}_2$

• As a result, the degree of covalent character rises with increasing order.

$\mathrm{NaCl}<\mathrm{LiCl}<{\mathrm{BeCl}}_2$