Arrange the following elements in increasing order of first ionization enthalpy: Li, Be, B, C, N
Choose the correct answer from the options given below:
Explanation:
Ionization enthalpy generally increases across a period from left to right. However, there are exceptions due to electronic configurations.
1. Lithium (Li): It has the lowest ionization enthalpy as it readily loses one electron to achieve a stable noble gas configuration.
2. Boron (B): Boron has a slightly lower ionization enthalpy than beryllium because removing a p-electron from boron is easier than removing an s-electron from the filled s-orbital of beryllium.
3. Beryllium (Be): Beryllium has a higher ionization enthalpy than lithium due to its smaller size and higher effective nuclear charge. Also it has a completely filled 2s orbital.
4. Carbon (C): Carbon has a higher ionization enthalpy than boron due to its increased nuclear charge and smaller atomic radius.
5. Nitrogen (N): Nitrogen has an exceptionally high ionization enthalpy because it has a half-filled p-orbital configuration (2p³), which is particularly stable. Removing an electron disrupts this stable configuration.
Therefore, the increasing order of first ionization enthalpy is:
Li < B < Be < C < N
Conclusion:
The correct order is Li < B < Be < C < N
List I | List II | ||
---|---|---|---|
A | Mesozoic Era | I | Lower invertebrates |
B | Proterozoic Era | II | Fish & Amphibia |
C | Cenozoic Era | III | Birds & Reptiles |
D | Paleozoic Era | IV | Mammals |