What do you mean by ionization energy? What are the factors which determine the magnitude of ionization of energy?

Ionization energy can be described as a measure of the difficulty in removing an electron from an atom or ion or the tendency of an atom or ion to surrender an electron. The more electrons that are lost, the more positive this ion will be, the harder it is to separate the electrons from the atom. The loss of electrons usually happens in the ground state of the chemical species. The factors that determine the magnitude of ionization energy are as follows: (i) Nuclear charge: Nuclear charge is essentially the electrostatic attraction that the positively charged protons exert on the outermost electrons. This is directly proportional to the number of protons present in the nucleus. (ii) Screening/Shielding effect: Screening or shielding effect refers to this reduction of the electrostatic force of attraction as the inner shell electrons “shield” the valence electrons from the full attractive force from the nucleus.