IONISATION ENERGY
by Syafiqah Yustri
1. The minimum energy needed to remove an electron from gaseous atom or ion in its ground state. It is a endotermic process
1.1. unit KJ/mol
2. Factor Affecting The Ionisation Energy
2.1. Atomic Radius
2.2. Effectiive Nuclear Charge (Zeff)
2.3. Shielding Effect
3. Less attraction between valence electron and nucleus when atom have larger atomic radius. This causes low ionisation energy.
4. The higher the Zeff , the stronger the attraction forces between the nucleus and electrons. This causes high ionisation energy.
5. Outer electrons will be less attracted to the nucleus because of the shielding effect of the electrons in the inner shells. This causes decreasing of ionisation energy.
6. 1st ionisation energy
6.1. minimum energy needed to remove one valence electron of a neutral gaseous atom in its ground state.
7. 2nd ionisation energy
7.1. energy needed to remove one electron from a positive gaseous ion its ground state.
8. the lower of EI, the more easier electron can be removed to form cation.
9. When moving across a period
9.1. Zeff increase, atomic size decrease.
9.1.1. Valence electron closer to the nucleus, attraction between the nucleus and the valence electrons become stronger.
9.1.1.1. More energy needed to remove the valence electron from an atom. Thus, IE increase.