Ionization Potential and their Variation in Periodic Table
Ionization Enthalpy MCQs
Ionization Potential or Ionization Energy or Ionization Enthalpy
The minimum amount of energy required to remove an electron from an isolated gaseous atom to produce a cation is called ionization potential.Since it is energy so expressed in KJ/mol or in ev/atom.(1ev = 97.5KJ)
Experimental value of I.P is 2.18 x 10-18 x Z*/n2J.
Or, I.P is directly proportional to Z*/n2
where, Z* is effective nuclear charge and n is orbit number
Greater the Z*, greater the I.P and larger the atomic radius lower is the I.P.
It is the property of metals. Smaller the value I.P., easier the ease of formation of cation.
The value of IPI is smaller than that of IPII and the value of IPII is less than that of IPIII.
i.e. IPI < IPII < IPIII
Factors Affecting the Ionization Potential
1. Nuclear Charge2. Atomic Size
3. Penetrating effect of the electron
4. Screening effect of the inner shell electron And
5. Electronic configuration
Nuclear Charge
I.P increases with increase in nuclear charge because, with increase in nuclear charge the electron in outer shell are more tightly held by the nucleus and thus more energy required to remove an electron from the atom.Atomic Size
I.P decreases with increasing the atomic size because, the distance of outer electron from the nucleus increases with size and thus the force of attraction decreases and electron in the outer shell held with nucleus less firmly and less amount of energy is required to remove an electron from the atom.Penetrating Effect
I.P increases as penetrating of the electron increases. Within the same shell the penetrating effect is in order--- s > p > d > f. If the penetrating effect of the electron is more, the electrons are closer to the nucleus and held firmly. Consequently more energy is required to remove an electron from the atom.Screening Effect
I.P decreases when screening effect (repulsive force felt by the valence shell electrons from the electrons present in the inner shell) increases.Electronic Configuration
Atoms having the half filled or full filled configurations are more stable and extra energy required to remove an electron.Variation of Ionization Potential in Periodic Table
Share
