JEE MAIN - Chemistry (2022 - 25th July Evening Shift - No. 5)
The first ionization enthalpies of Be, B, N and O follow the order
O < N < B < Be
Be < B < N < O
B < Be < N < O
B < Be < O < N
Explanation
The first ionization energy increase from left to right along $2^{\text {nd }}$ period with the following exceptions
$$\mathrm{IE}_{1}: \mathrm{Be}>\mathrm{B}$$ and $$\mathrm{N}>\mathrm{O}$$
This is due to stable configuration of $$\mathrm{Be}$$ in comparison to $$\mathrm{B}$$ and that of $$\mathrm{N}$$ in comparison to $$\mathrm{O}$$.
Hence the correct order is $$\mathrm{N}>\mathrm{O}>\mathrm{Be}>\mathrm{B}$$
$$\mathrm{IE}_{1}: \mathrm{Be}>\mathrm{B}$$ and $$\mathrm{N}>\mathrm{O}$$
This is due to stable configuration of $$\mathrm{Be}$$ in comparison to $$\mathrm{B}$$ and that of $$\mathrm{N}$$ in comparison to $$\mathrm{O}$$.
Hence the correct order is $$\mathrm{N}>\mathrm{O}>\mathrm{Be}>\mathrm{B}$$
Comments (0)
