Ionization Energy: The energy required to remove an electron from the outer most orbit of a neutral gaseous atom is called Ionization energy.
Effecting factors of Ionization Energy :
(1) Nuclear charge : More the nuclear charge more is the Ionization Energy.
(2) Screening or shielding effect : More the screening effect, less is the Ionization Energy
(3) Penetration power of the orbitals : More the penetration power, more is the Ionization Energy.
(4) Stable configuration : More the stable configuration more is the Ionization Energy.
(5) Atomic radius : More than the atomic radius, less is the Ionization Energy.
