Question

The $I{{E}_{1}}$ value of $Li,Be$ and $C$ are $5.4eV$ per atom, $9.32eV$ per atom and $11.26eV$ per atom. The $I{{E}_{1}}$ value of boron is:
A. $13.6\,eV$ per atom
B. $8.29\,eV$ per atom
C. $14.5\,eV$ per atom
D. $21.5\,eV$ per atom

Answer 1

Ionization enthalpy is defined as the amount of energy that is required to remove an electron from its isolated gaseous atom in its gaseous state. Factors on which ionization enthalpy depends are penetration effect, electronic configuration and shielding effect.

Complete step by step answer:
The first ionization energy is defined as the energy required to remove an outermost electron from its neutral atom in the gas phase. Lithium atom contains three protons in its nucleus, to remove an electron lithium atom, the reaction can be written as follows:
$L{{i}_{(g)}}\to L{{i}^{+}}_{(g)}+{{e}^{-}}$
$\Delta {{H}_{i}}=5723\,kJ/mol$
Lithium, beryllium and carbon belong to the period. So, as we move along the period, ionization potential increases, therefore, carbon has the highest ionization potential among the given elements and lithium has lowest ionization potential. It also satisfies the given data, that means, carbon $(C)$ having $11.26\,eV$ per atom ionization potential and lithium $(Li)$ having $5.4eV$ per atom ionization potential.
Now, we come to beryllium $(Be)$ and boron $(B)$ , in which beryllium having electronic configuration as: $1{{s}^{2}}2{{s}^{2}}$ and boron having electronic configuration as: $1{{s}^{2}}2{{s}^{2}}2{{p}^{1}}$ . As we can see, beryllium is having a fulfilled orbital whereas boron does not have a fulfilled orbital. Therefore, it can be observed that beryllium is more stable than boron. This means that more energy is required to remove electrons from beryllium than from boron. So, beryllium has higher ionization potential than boron.
Therefore, the correct order of increasing ionization potential for the given elements can be given as:
$Li < B < Be < C$.
So, we can conclude that the value of ionization potential of boron must lie between that of lithium and beryllium and considering the given data for the values of ionization potential of each element, the best possible value of the ionization potential of boron would be $8.29\,eV$ per atom.

So, the correct answer is Option B.

Note: The ionization energy is a property of elements in the periodic table, which increases as we move along a period.
Even though beryllium is placed before boron in the period, beryllium still has slightly more ionization energy than boron due to the stability of its atom.