1. Orbital energies II/

2. Orbital Energy determined by n and ℓ: The larger (n+ℓ), the higher the energy. If two orbitals have equal (n+ℓ), that with larger n has higher energy. 1s 1 2s 2p 2 3 3s 3p 3d 3 4 5 4s 4p 4d 4f 4 5 6 7 5s 5p 5d 5f 5g 5 6 7 8 9 6s 6p 6d 6f 6g 6h 6 7 8 9 10 11c Orbital (n+ℓ) II/

3. Electron motions Spin motion: Rotation around itself Orbital motion: Rotation around nucleus Only two possibilities right up left down x y z e-e- nucleus +½ ↔ -½ II/14

4. Pauli Exclusion Principle No two electrons in an atom can be equal in all four quantum numbers. 1s 2s 2p 1 st e - n=1 ℓ=0 m ℓ =0 m s =+½ 2 nd e - n=1 ℓ=0 m ℓ =0 m s =+½ Energy  2 nd e - n=1 ℓ=0 m ℓ =0 m s =-½ 3 rd e - n=1 ℓ=0 m ℓ =0 m s = ± ½  → Only two electrons fit in one orbital. II

5. 2p mℓmℓ -1 0 1 p x p z p y II/

6. Electron configuration and Aufbau Principle  Electrons are placed first in the lowest empty energy levels.  Two electrons with opposite spin in each orbital.  For electrons with the same ℓ-value, the most stable state is that with maximum spin (Hund’s rule). 2p Spin=+½ -½=0 Spin=+½ +½=1 II/

7. 1s 1 2s 2p 2 3 3s 3p 3d 3 4 5 4s 4p 4d 4f 4 5 6 7 3s 4p 5s 4s 2s 1s 3p 2p 3d 4d E z H1 electron configuration 1s 1 (meaning one electron in the 1s orbital) He2 1s 2 Li3 1s 2 2s 1 or [He] 2s 1 Be41s 2 2s 2 or [He] 2s 2 B5 1s 2 2s 2 2p 1 or [He] 2s 2 2p 1 C6 1s 2 2s 2 2p 2 or [He] 2s 2 2p 2 (Hund’s Rule) N71s 2 2s 2 2p 3 or [He] 2s 2 2p 3 (Hund’s Rule) O8 1s 2 2s 2 2p x 2 2p y 1 2p z 1 or [He] 2s 2 2p 4 F91s 2 2s 2 2p x 2 2p y 2 2p z 1 or [He] 2s 2 2p 5 Ne101s 2 2s 2 2p x 2 2p y 2 2p z 2 or [He] 2s 2 2p 6 II/

8. Periodic table II/

9. 1s 1 2s 2p 2 3 3s 3p 3d 3 4 5 4s 4p 4d 4f 4 5 6 7 3s 4p 5s 4s 2s 1s 3p 2p 3d 4d E Na : [Ne] 3s 1 Mg : [Ne] 3s 2 Al : [Ne] 3s 2 3p 1 Si : [Ne] 3s 2 3p x 1 3p y 1 P : [Ne] 3s 2 3p x 1 3p y 1 3P z 1 S : [Ne] 3s 2 3p x 2 3p y 1 3P z 1 Cl : [Ne] 3s 2 3p x 2 3p y 2 3P z 1 Ar : [Ne] 3s 2 3p x 2 3p y 2 3P z 2 K : [Ar] 4s 1 Ca : [Ar] 4s 2 Sc : [Ar] 4s 2 3d 1 II/

11. n of outermost shell No. of group: No. of electrons in outermost shell (no. of valence electrons) 1-8 Period number 1 2 3 7 4 5 6 II/

12. Valence shell: outermost occupied main shell Valence electrons: electrons that occupy the outermost main shell electrons with highest n determines the chemistry of element II/

13. Electron configuration from periodic table Se[Ar] 4s 1 3d 10 4p 4 Ru[Kr] 5s 2 4d 6 In[Kr] 5s 2 4d 10 5p 1 Ba[Xe] 6s 2 Au[Xe] 6s 2 4f 14 5d 9 [Xe] 6s 1 4f 14 5d 10 II/