Question

Compare the ionization energy of Be and B.

Answer 1

In the given question ionization energy has been discussed. The ionization energy is the energy of an atom in the periodic table is the amount of energy which is required to eliminate an electron from a mole of atoms in the gaseous phase.

Complete Step by step answer: We all know that the ionization energy increases when we go from left to right side in a periodic table, and there are some distinct cases in which this general rule is not followed or accepted in some elements in periodic table.
Although the ionization energy of Boron is lower than that of Beryllium, while according to the general trend there should be higher ionization energy of Boron than Beryllium.
The reason behind this exception occurs is that Boron has only one electron in the $p$ orbital and we know that $p$ orbital has higher energy than that of $s$ orbital, so this electron in the p orbital have a tendency to go to a lower energy level or may be lose in direction to make the atom more stable. As it is said that the lower the energy, the more stable the atom will be.
Therefore, the energy required to remove one electron from the $p$ orbital of Boron is lower than the one required to remove one electron from the $s$ orbital of Beryllium which is fully filled.

Hence, the ionization energy of Boron is lower than that of Beryllium.

Note: There are some variations in these general trends. For example, the first ionization decreases from beryllium to boron as electrons from the p-block start to take part. As In the case of boron, it has an electron configuration of $1{s^2}2{s^2}2{p^1}$, the $2s$ electrons shield the higher-energy $2p$ electron from the nucleus, making it easier to remove.