According to Fajan's Rules, arrange and in increasing order of covalent character. — Chemical Bonding Chemistry Question

💡 Solution & Explanation

Covalent character increases with the polarizing power of the cation, which is proportional to charge/size ratio ($\phi$). As charge increases ($Li^+ < Be^{2+} < B^{3+} < C^{4+}$) and size decreases, polarizing power and covalent character increase.