Question

Which of the following is highly covalent?

• A. $Al{F}_3$
• B. $AlC{l}_3$
• C. $AlB{r}_3$
• D. $CC{l}_4$

Answer 1

The correct option is D $CC{l}_4$

Down the periodic table, generally the size of atoms increases. So carbon will be smaller in size as compared to aluminium. Now, from fajan's rule of polarization, smaller the size more is the polarizing power, so more is the covalent character. Since carbon has the smallest size, $CC{l}_4$ will have maximum covalent character. Also, Higher the charge on cation, higher is the covalent character. So, $D$ is the correct answer.