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Unformatted text preview: EE372 Assignment 5 Solutions 1. Ionization energy and screening In a multi-electron atom, inner electrons partially screen the nuclear charge so that outer electrons feel a weakened Coulomb force. One can define an effective nuclear charge seen by outer electrons by using the hydrogenic energy equation E = (- 13 . 6eV)( Z eff /n ) 2 for the outer electron’s energy. When the outer electron’s energy is measured by chemists, it is called the ionization energy which is the amount of energy required to remove the electron from the atom. a) Lithium ( Z = 3) has a single 2s electron outside the full K shell core. The ionization energy is 5.37 eV. Determine Z eff . Notice how effective the two core electrons are at screening the nuclear charge. b) Singly ionized lithium (Li + ) has only the two 1s electrons having lost the 2s electron. The ionization energy is 76.3 eV. Determine Z eff . Notice that the other 1s electron is not as effective at screening the nuclear charge. c) Sodium ( Z = 11) like lithium has a single electron outside a full core, [Ne]3s 1 . The ionization energy is 5.12 eV. Determine Z eff . Notice that the core electrons are not as effective at screening the nuclear charge in sodium as in lithium. d) Copper ( Z = 29) has the electronic configuration [Ar]3d 10 4s 1 . Removing the 4s electron requires an ionization energy of 7.69 eV. Determine Z eff . Notice that the 3d electrons are not nearly as effective at screening the nuclear charge....
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- Fall '10
- Electron, Atomic orbital, Electron shell, ev