Question

The correct order of ionization potential values of \[Be,{\text{ }}B,{\text{ }}Li,{\text{ }}C\]atom is:
1.$Be < B < Li < C$
2.$Li < Be < B < C$
3.$Li < Be > B < C$
4.$Li > Be > B < C$

Answer 1

Hint:The formation of ions is caused by either release or gain of electrons. The energy required to remove an electron from \[1\] mole of atoms of a gas is known as the ionization energy.
\[M\left( g \right)\;\; \to {M^ + }\left( g \right)\;{\text{ }} + \;\;{e^ - }\]
When energy is needed to go from neutral atoms to cations with \[1 + \]charge, this is more precisely called first ionization energy and this is called so as it is possible to remove more electrons from most elements.

Complete step-by-step answer:The second ionization energy is the energy that is required to remove a second electron, to form $2 + $cations from \[1 + \] cations. For this, we must have a cation with \[1 + \]charge. Equation for this is:
\[{M^ + }\left( g \right)\;\; \to {M^{2 + }}\left( g \right)\;{\text{ }} + \;\;{e^ - }\]
The third ionization energy is the energy required to form 3+ cations:
\[{M^{2 + }}\left( g \right)\;\; \to \;{\text{ }}{M^{3 + }}\left( g \right)\;{\text{ }} + \;\;{e^ - }\]
and so on. 
Always positive numbers as to this process to occur energy must be supplied thus ionization process is an endothermic energy change. This occurs as separating an electron from an atom isn’t easy. The second ionization energy for any particular atom of any element is always larger than the first ionization energy. This is because it requires a much larger amount of energy to remove an electron from a cation than it is from a neutral atom.
Thus when we talk about the above atoms, we must know the order to be:
\[Li < Be > B > C\]
This is because as we go from left to right in a periodic table, the ionization potential increases. However, \[Be\]has greater Ionization Potential than\[\;B\] due to stable full-filled \[2s\]-configuration of\[Be\]. It is not easy to remove an electron from such a configuration.

Note:When put into periodic table, the first ionization energy varies in a predictable way. As we go from top to bottom in a group, the ionization energy decreases. As we move across a period left to right, ionization energy increases. Thus, helium has the largest first ionization energy, while francium has one of the lowest.