For Mini-quiz 31

sdpsdp 3d 4d 5d 6d He is s not p IN-CLASS EXERCISES : COMPLETE ELECTRONIC CONFIGURATIONS (Doing the `Aufbau’=building up)

IN –CLASS EXERCISECHEM Write the complete electron configuration for the elements below a)Cl b)K c) Mn d ) Se 1s 2 2s 2 2p 6 3s 2 3p 5 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 5 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4

Which configuration is incorrect below ? (Use your Periodic Tables to figure out) A.1s 2 2s 2 3s 1 B.1s 2 2s 2 2p 3 C.1s 2 2s 2 2p 6 3s 2 D.1s 2 2s 2 2p 6 3s 2 3p 5

What is the correct complete electronic configuration for Ca? A.1s 2 2s 2 2p 6 3s 2 3p 6 B.1s 2 2s 2 2p 6 3s 2 C.1s 2 2s 2 2p 6 3s 2 3p 6 4p 1 D.1s 2 2s 2 2p 6 3s 2 3p 6 4s 2

1s 2 2s 2 2p 6 3s 2 3p 5 Abbreviated Configurations Complete configuration for Cl =[Ne] `core’ =Outermost `valence’ shell [Ne] Valence shell Abbreviated configuration for Cl [Ne] 3s 2 3p 5

Write the abbreviated electron configurations for the elements below, assuming Periodic Table arrangement for filling a ) Ca b) Al c) As [ Ar] 4s 2 [ Ne] 3s 2 3p 1 [Ar] 4s 2 3d 10 4p 3

What is the correct, abbreviated configuration for Mg ? A.[ Na]3s 2 B.[He][Ne]3s 2 C.[Ne]3s 2 D.[He]2s 2 2p 6 3s 2

d electron variations Mn 1) s d electron configuration switching [Ar] 4s 2 3d 5 [Ar] 3d 5 4s 2 [Ar] 3d 5 From spectra of atomized elements As it behaves chemically in solution Mn 2+ Evidenced by fact that all transition metals have a stable 2+ state… => outer 4s 2 are removed first Example: behavior of Mn

2.3. Write the correct, abbreviated d-switched configurations for the transition metals below a) Cu b) Fe 2+ c) Zn 2+ [Ar] 3d 9 4s 2 (3d and 4s switch order) [Ar] 3d 6 (outer 4s electrons lost first) [Ar] 3d 10 (outer 4s electrons lost first)

Which is the correct, abbreviated d- switched configuration for Cr A.[Ar] 4s 2 3d 4 B.[Ar]4s 2 4d 2 C.[Ar]4s 2 3d 2 D.[Ar]4s 2 4d 4

2) s and d undergo filled/half- filled/empty rearrangements Cr +1 [Ar] 3d 4 4s 1 [Ar] 3d 5 4s 0 STILL WRONG  RIGHT based on chemistry and spectroscopy [Ar] 4s 2 3d 3 Periodic Table predicts Corrected for chemistry by d- switching d-electron variations (continued)

Pigeonhole 1 representation of electrons [Ar] 3d 4 4s 1 Cr + = As implied by Table + chemical reversal 4s 3d Pigeonhole representation D switch rule: s and d electrons in valence shell move around to produce filled, half-filled and/or empty orbitals in order to attain a more stable atom. Corrected for filled,half-filled, empty rule [ Ar]3d 5 4s 0 *This final moving around applies only for transition metals After fill, half-filled, empty correction 1 Called orbital diagrams in text [Ar]

d switch rule: s and d electrons in valence shell move around to produce filled, half- filled and/or empty orbitals in order to attain a more stable atom. If element only has s and p….it means no switching….