Regarding ionization potential some statement
are given

A) Ionization process is an endothermic process
B) The order of IP values is IP₁ < IP₂ < IP₃
C) With increases in the number of electrons
in the shells. The I.P. values gradually
increase
D) Stable configuration leads to greater I.P
value
E) In a period the I.P. value decreases from
left to right
Correct in the above statements

We know that Ionization energy is the minimum energy required to remove the most loosely held electron from one mole of gaseous atoms to produce one mole of gaseous atoms.

Hence, It is an endothermic reaction.

Therefore, Statement 1 is correct.

Now,We know that Ionisation energy increases as we move left to right in a period and decreases as we move down the group.

Hence, Statement 5 is incorrect

The order of IP values is ${\mathrm{IP}}_1<{\mathrm{IP}}_2<{\mathrm{IP}}_3$

Therefore, Statement 2 is correct.

With increases in the number of electrons in the shells. The I.P. values gradually increase.

Statement 3 is also true because as we move along a period non-metallic character increases and the energy required to remove the electrons also increases.

We know that more stable the configuration more energy is required to remove the electron as they are tightly bound to each other.

Hence, Statement 4 is also correct.

Therefore, option(C) is the answer.