Zumdahl (pp [atomic properties] ), [ionic radii] )

Transcription

1 Chemistry 1B-AL Fall 2016 advetures lectures 7-8 Zumdahl (pp [atomic properties] ), [ioic radii] ) 1

2 Chemistry 1B AL Electroic Structure ad Periodic Properties of Atoms 2

3 Zumdahl (pp [atomic properties] ), [ioic radii] ) 3

4 worksheet IV- sectios I.1-I.3 ad upcomig clickeroos 4

5 periodicity (figure 12.29) Lavoisier 1789 Newlads 1863 Medeleev

6 EXPLAIN THIS!!!! (atomic radii, fig ) atomic radii (10-12 m): Li 152 Na 186 K 227 Rb 247 Cs 265 Fr 270 icrease atomic umber of atom but Li 152 Be 113 B 88 C 77 N 70 O 66 F 64 Ne 69* 6

7 explai this Na (s) + ½Br 2 ( ) Na + Br (s) why Na +? why Br? 7

8 periodicity (figure 12.29) VOILA!!! 8

9 bad joke 9

10 periodic properties of atoms ad their ios gas phase eergy of electro with, Z ( ) E J IE = eff 2 ( J) Z Z 2 18 eff 2 eff "Bohr" radius i gas phase 2 10 r ( m) Z eff r (52.9pm) Z pm= eff m (picometer) 10

11 basic treds for ad Z eff i periodic table (figure 8.9, Silberberg) Z eff across dow 11

12 basic treds for ad Z eff i periodic table (figure 8.9, Silberberg) Z eff across for each sequetial atom a proto ad a electro i same shell is added: for a outermost (valece) electro: : stays the same as oe goes across a row Z eff : add +1 to Z (actual uclear charge), icreases attractio add electro i same shell; repulsio shields other electro but ot full -1 repulsio sice i same shell 12

13 basic treds for ad Z eff i periodic table (figure 8.9, Silberberg) Z eff icreases across row (period) is ot chagig 13

14 basic treds for ad Z eff i periodic table (figure 8.9, Silberberg) Z eff for each sequetial atom, complete ier shells are added: for a outermost (valece) electro: : icreases by 1 as oe goes dow a colum Z eff : add same umber of protos ad electros (e.g. 8 i goig period 2 3) but electros are ier shell so almost complete shieldig so uclear attractio ad electro repulsio (shieldig) cacel dow 14

15 basic treds for ad Z eff i periodic table (figure 8.9, Silberberg) Z eff icreases across row (period) icreases dow colum (group ) Z eff is relatively costat is ot chagig 15

16 Estimatig atomic radii (metallic ad covalet) (figs. Zumdahl 12.37, Silberberg 8.14) for metals for ometalsca vary from compoud to compoud 16

17 covalet ad metallic atomic radii periodic treds (fig ) Z eff gas phase 'Bohr' radius r ( m) Z do't take formula too 'literally' for metallic/covalet radii 2 eff but : larger larger r larger Z eff smaller r 17

18 atomic radii (Silberberg fig. 8.15) umerical values differ slightly from Zumdahl Z eff gas phase 'Bohr' radius r ( m) Z do't take formula too 'literally' for metallic/covalet radii 2 eff but : larger larger r larger Z eff smaller r 18

19 atomic radii (Silberberg fig. 8.15) umerical values differ slightly from Zumdahl Z eff gas phase 'Bohr' radius r ( m) Z do't take formula too 'literally' for metallic/covalet radii 2 eff but : larger larger r larger Z eff smaller r trasitio metals ( special cosideratios) 19

20 radii for trasitio metal (eutral) atoms i 4 th period Eve though the E 4s < E 3d (due to peetratio effects), the average positio (radius) of the 3d oribtals is somewhat smaller. Thus, i terms of atomic size, the 4s is the outermost orbital for all of the atoms; ad as oe goes across the period, successive e s are added to ier 3d orbitals ad the radii are relatively costat. 20

21 radii of ios (F vs F ) r /Z eff pm how would the radius of F compare to that of F? F 1s 2 2s 2 2p 5 F 1s 2 2s 2 2p 6 outer electro =2 for both, Z uclear =+9 for both how does Z eff for 2p i F compare to Z eff for 2p i F? o 2p e i F is shielded by 4? electros i same subshell o 2p e i F is shielded by 5? electros i same subshell o (Z eff ) F >? (Z eff ) F radius (F) < radius (F )? Experimet: F: r=64 pm F : r=136 pm (fig ) (fig. 13.8) 21

22 for today 22

23 o rest for the weary!! Moday, 17 October!!! after midterm iclicker-check-up Video 4 Study Guide 4 I-IV the whole thig! How s your CHEM1B-AL health? 23

24 worksheet IV : how do Z eff ad vary across ad dow periodic table? 24

25 worksheet IV: how do Z eff ad compare for eutrals ad ios? 25

26 more examples of comparig radii Na vs Na + Ne vs Na + (ote experimetal data for Na +, fig ad Ne, fig ot comparable see) O 2 vs F O 2 vs F 26

27 ioizatio eergies (IE s) eergy required to remove a electro from a gaseous atom (io) X (g) + (eergy=ie) X(g) + + e - as i chapter 9: eergy positive (+) whe absorbed i reactio (edothermic) eergy egative ( ) whe released i reactio (exothermic) IE s geerally positive 27

28 ioizatio eergies ( Zumdahl fig , Silberberg, fig. 8.18) gas phase eergy of electro with, Z E larger Z eff 18 Zeff ( J) 2 IE = E larger smaller IE eff larger IE 2 exceptios N > O, P > S, As Se why? Be > B, Mg > Al, Ca Ga why? 28

29 successive gas phase ioizatio eergies i kj/mol (p572; S6) Al ([He]2s 2 2p 6 3s 2 3p 1 ) Al + ([He]2s 2 2p 6 3s 2 ) + e IE 1 = 580 Al + ([He]2s 2 2p 6 3s 2 ) Al 2+ ([He]2s 2 2p 6 3s 1 ) + e IE 2 = 1815 Al 2+ ([He]2s 2 2p 6 3s 1 ) Al 3+ ([He]2s 2 2p 6 ) + e IE 3 = 2740 Al 3+ ([He]2s 2 2p 6 ) Al 4+ ([He]2s 2 2p 5 ) + e IE 4 = 11,600 successive IE s get larger (positively charged ios have greater Z eff ) large jumps i IE whe of electro removed chages 29

30 electro affiities (EAs, pp ) the eergy of the reactio whe a electro is added to a atom X(g) + e X (g) + (eergy = EA) egative EA meas eergy give off (exothermic) positive EA meas io ustable relative to eutral atom (some older texts use opposite) 30

31 electro affiities (Zumdahl fig 12.36; Silb fig. 8.20) Z eff higher smaller (less egative) EA larger Zeff larger (more egative) EA positive EA egative io ustable [harder to measure ad less regular tha I.E. s] 31

32 F vs Cl electro affiities (Zumdahl p 577) Z eff higher smaller (less egative) EA small size of F HW #3 Prob 27a 32

33 Joural of Fluorie Chemistry

34 summary (Silb, fig. 8.21) Z eff gas phase eergy of electro with, Z E 18 Zeff ( J) 2 2 eff gas phase 'Bohr' radius 10 r ( m) Z 2 eff EAs get more egative 34

35 Zumdahl (sectio 12.16, figure 12.39) ot resposible for pp BUT 35

36 reactivity ad periodic structure (Silberberg figure 8.22) metallic vs o-metallic behavior IE ad EA meltig poit ad coductivity acid-base behavior of oxides (ot resposible 1B before 1A) 36

37 periodic table of comic books 37

38 , Z eff 18 ( J) IE = + 10 r ( m) Z 2 Z eff 2 eff 2 END OF LECTURES ADVENTURES

39 comparig Na + to Ne (similar experimetal measures) Zum fig Zum ~ fig 13.8 Na + 95 pm Ne all 10-electro atoms/ios isoelectroic cofiguratios Z (ad Z eff ) decrease Z (ad Z eff ) icrease larger radius smaller radius 39

40 figure Silberberg

41 Silberberg figure 8.23 o-metal meltig poit, coductivity decrease metal meltig poit, coductivity decrease o-metal 41

42 team 2-miute max sectio explaatios exceptios to ioizatio potetial tred of icreasig as oe goes across periodic table!! exceptios N > O, P > S, As Se why? team 1 i each sectio Be > B, Mg > Al, Ca Ga why? team 2 i each sectio 42