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Full text of "Transparencies Unit 5 - Models of the Atom: Project Physics"

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The Project Physics Course 



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Unit O Transparencies 



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Models of the Atom 



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The 
Project 
Physics 
Course 



Transparencies 



5 



UNIT 

Models of the Atom 







Published by HOLT, RINEHART and WINSTON, Inc. New York, Toronto 



Project Physics 

Overhead Projection Transparencies 

Unit 5 

T35 Periodic Table 

T36 Photoelectric Experiment 

T37 Photoelectric Equation 

T38 Alpha Scattering 

T39 Energy Levels — Bohr Theory 



m 

f- 



Periodic Table 



T35 



Periodic Table 



This transparency will be useful in discussions centered around the classification of the elements. 
Various overlays highlight chemical families and other pertinent groupings. 

Overlay A The modern long form of the Periodic Table. The number below each chemical symbol 
represents the element's atomic number. The Roman numerals identify the Groups or 
Families. The numbers to the left of Group I identify the Periods. 

Overlay B This includes the 62 elements which Mendeleef included in his 1872 classification. His 
grouping was, of course, unlike the present long form. Rather it resembled the modern 
"short" form of the Table. Remove this overlay. 

Overlay C The Alkali Metal Family (Group I). 

Overlay D The Halogen Family (Group VII). 

Overlay E The Noble Gas Family (Group O). 

Overlay F The elements known as the Transition Elements. Remove Overlays C, D. E. and F. 

Overlay G The Natural Radioactive Elements. Those which undergo J-decay only are tinted 
lighter. Technetium (Tc, Atomic Number 43) is a synthetic element. 

Overlay H The Transuranium Elements. These have all been synthesized in the laboratory. 



T-35 



Periodic Table of the Elements 



1 



T5 
O 

'^ 4 







H 

1 


II 




III 


IV 


V 


VI 


VII 


He 

2 


Li 

3 


Be 

4 




B 

5 


c 

6 


N 

7 




8 


F 

9 


Ne 

10 


Na 
II 


Mg 


Al 

13 


Si 

14 


P 

15 


s 

16 


CI 

17 


Ar 

18 


K 

19 


Ca 

20 


Sc 

21 


Ti 

22 


V 

23 


Cr 

24 


Mn 

25 


Fe 

26 


Co 

27 


Ni 

28 


Cu 

29 


Zn 

30 


Ga 

31 


Ge 

32 


As 

33 


Se 

34 


Br 

35 


Kr 

36 


Rb 

37 


Sr 

38 


Y 

39 


Zr 

40 


Nb 

41 


Mo 

42 


Tc 

43 


Ru 

44 


Rh 

45 


Pd 

46 


Ag 

47 


Cd 

48 


In 

49 


Sn 

50 


Sb 

51 


Te 

52 


1 

53 


Xe 

54 


Cs 

55 


Ba 

56 


1 


Hf 

72 


Ta 

73 


w 

74 


Re 

75 


Os 

76 


Ir 

77 


Pt 

78 


Au 

79 


Hg 

so 


TI 

8! 


Pb 

82 


Bi 

83 


Po 

84 


At 

85 


Rn 

86 


Fr 

87 


Ra 

S8 


• 
• 
• 
• 

































La 

57 


Ce 

58 


Pr 

59 


Nd 

60 


Pm 

61 


Sm 

62 


Eu 

65 


Gd 

64 


Tb 

65 


Dy 

66 


Ho 

67 


Er 

68 


Tm 

69 


Yb 

70 


Lu 

71 


Ac 

89 


Th 

90 


Pa 

91 


U 

92 


Np 

93 


Pu 

94 


Am 

95 


Cm 

96 


Bk 

97 


a 

98 


Es 

99 


Fm 

100 


Md 

101 


No 

102 


Lw 

103 



TRK 



Periodic Table of the Elements 



B 



1 


1 

H 




1 


Elements Inck 


ided in 


1872 
















He 


1 


II 


Mendeleef Classification 


ill IV V VI VII 


2 


2 


Li 


Be 




B 


c 


N 


o 


F 


Ne 


3 


4 




5 


6 


7 


8 


9 


10 


'^ 


Na 


Mg 


Al 


Si 


P 


s 


CI 


Ar 


3 


II 


12 




13 


14 


15 


16 


17 


18 


o 

^ A 


K 


Ca 


Sc 


Ti 


V 


Cr 


Mn 


Fe 


Co 


Ni 


Cu 


Zn 


Ga 


Ge 


As 


Se 


Br 


Kr 


<D 4 
Q- 


19 


20 


2 


22 


23 


24 


25 


26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 


c 


Rb 


Sr 


Y 


Zr 


Nb 


Mo 


Tc 


Ru 


Rh 


Pd 


Ag 


Cd 


In 


Sn 


Sb 


Te 


1 


Xe 


5 


37 


38 


39 


40 


41 


42 


43 


44 


45 


46 


47 


48 


49 


50 


51 


52 


53 


54 


6 


Cs 


Ba 


' 


Hf 


Ta 


w 


Re 


Os 


Ir 


Pt 


Au 


Hg 


TI 


Pb 


Bi 


Po 


At 


Rn 


55 


56 


"• 


72 


73 


74 


75 


76 


77 


78 


79 


80 


81 


82 


83 


84 


85 


86 


7 


Fr 


Ra 


' 




/ 


87 


^s 


• 
• 

































La 

■■ 57 


Ce 

58 


Pr 

59 


Nd 

60 


Pm 

61 


Sm 

62 


Eu 

6i 


Gd 

64 


Tb 

65 


Dy 

66 


Ho 

67 


Er 

6% 


Tm 

69 


Yb 

70 


Lu 

71 


Ac 

■•. 89 


Th 

90 


Pa 

9 


U 

92 


Np 

93 


Pu 

94 


Am 

95 


Cm 

^6 


Bk 

97 


a 

98 


Es 

99 


Fm 

100 


Md 

101 


No 

102 


Lw 

103 



m 



1 


1 

H 

1 


11 


Periodic Table of the Elements 
Alkali 

Metals 

III IV 


Noble. 
Gases 

V VI 


• 
• 

• 

VII 




He 

2 


2 


Li 


Be 


\ 


B 


c 


N 





F 


Ne 


^ 


3 


4 




5 


6 


7 


8 


9 


10 


3 


Na 


Mg 


Al 


Si 


P 


S 


CI 


Ar 


II 


Q 




13 


14 


15 


16 


17 


18 


O 

'^ 4 

0- 


K 


Ca 


Sc 


Ti 


V 


Cr 


Mn 


Fe 


Co 


Ni 


Cu 


Zn 


Ga 


Ge 


As 


Se 


Br 


Kr 


19 


20 


21 


22 


23 


24 


25 


26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 


5 


Rb 


Sr 


Y 


Zr 


Nb 


Mo 


Tc 


Ru 


Rh 


Pd 


Ag 


Cd 


In 


Sn 


Sb 


Te 


1 


Xe 


37 


38 


39 


40 


41 


42 


43 


44 


45 


46 


47 


48 


49 


50 


51 


52 


53 


54 


6 


Cs 


Ba 


*• 


Hf 


Ta 


w 


Re 


Os 


Ir 


Pt 


Au 


Hg 


TI 


Pb 


Bi 


Po 


At 


Rn 


\j 


55 


56 


• 


72 


73 


74 


75 


76 


77 


78 


79 


so 


81 


82 


83 


84 


85 


86 


7 


Fr 

87 


Ra 

S8 


• 
• 

• 


























Halogens 



La 

57 


Ce 

58 


Pr 

59 


Nd 

60 


Pm 

61 


Sm 

62 


Eu 

6i 


Gd 

64 


Tb 

65 


Dy 

66 


Ho 

61 


Er 

6S 


Tm 

69 


Yb 

70 


Lu 

71 


Ac 

89 


Th 

90 


Pa 

91 


U 

92 


Np 

93 


Pu 

94 


Am 

95 


Cm 

96 


Bk 

97 


a 

9S 


Es 

99 


Fm 

100 


Md 

101 


No 

102 


Lw 

103 



c 

D 
E 



TT3a5 



Periodic Table of the Elements 



1 


1 
H 




































He 


1 


II 




III IV V VI VII 


2 


2 


Li 


Be 




B 


C 


N 





F 


Ne 


3 


4 




5 


6 


7 


8 


9 


10 


3 


Na 


Mg 


Al 


Si 


P 


S 


CI 


Ar 


II 







13 


14 


15 


16 


17 


18 


o 

Q. 


K 


Ca 


Sc 


Ti 


V 


Cr 


Mn 


Fe 


Co 


Ni 


Cu 


Zn 


Ga 


Ge 


As 


Se 


Br 


Kr 


19 


20 


21 


22 


23 


24 


25 


26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 


5 


Rb 


Sr 


Y 


Zr 


Nb 


Mo 


Tc 


Ru 


Rh 


Pd 


Ag 


Cd 


In 


Sn 


Sb 


Te 


1 


Xe 


37 


38 


39 


40 


41 


42 


43 


44 


45 


46 


47 


48 


49 


50 


51 


52 


53 


54 


6 


Cs 


Ba 


■■, 


Hf 


Ta 


w 


Re 


Os 


Ir 


Pt 


Au 


Hg 


TI 


Pb 


Bi 


Po 


At 


Rn 


55 


56 


"• 


72 


73 


74 


75 


76 


77 


78 


79 


so 


SI 


82 


83 


84 


85 


se, 


7 


Fr 

87 


Ra 

88 


• 


Rad 


ioa 


ctiv 


eE 


em 


ent! 





















La 

57 

Ac 

89 



58 

Th 

90 



Pr 

59 

Pa 

91 



iNdl 

60_ 

U 

92 



Pm 

61 

Np 

93 



Sm 

62 

Pu 

94 



Eu 



Al 

95 



64 



Tb 

65 

Bk 

97 



a 

98 



Ho 

67 

Es 

99 



Er 

es 

Fm 

100 



Tm 

69 

Md 

101 



Yb 

70 

No 

102 



Lu 

71 

Lw 

103 



im 



Periodic Table of the Elements 



1 


1 

H 




































He 


1 


II 




III IV V VI VII 


2 


2 


Li 


Be 




B 


c 


N 





F 


Ne 


3 


4 




5 


6 


7 


8 


9 


10 


3 


Na 


Mg 


Al 


Si 


P 


S 


CI 


Ar 


II 







13 


14 


15 


16 


17 


18 


O 

« 4 

0. 


K 


Ca 


Sc 


Ti 


V 


Cr 


Mn 


Fe 


Co 


Ni 


Cu 


Zn 


Ga 


Ge 


As 


Se 


Br 


Kr 


19 


20 


21 


22 


23 


24 


25 


26 


27 


28 


29 


30 


3! 


32 


33 


34 


35 


36 


5 


Rb 


Sr 


Y 


Zr 


Nb 


Mo 


Tc 


Ru 


Rh 


Pd 


Ag 


Cd 


In 


Sn 


Sb 


Te 


1 


Xe 


37 


38 


39 


40 


41 


42 


43 


44 


45 


46 


47 


48 


49 


50 


51 


52 


53 


54 


6 


Cs 


Ba 


' 


Hf 


Ta 


w 


Re 


Os 


Ir 


Pt 


Au 


Hg 


TI 


Pb 


Bi 


Po 


At 


Rn 


55 


56 


. 


72 


73 


74 


75 


76 


77 


78 


79 


so 


81 


82 


83 


84 


85 


S6 


7 


Fr 

87 


Ra 

S8 


• 
• 


Rac 


lioa 


ctiv 


eE 


lem 


ent 


s .••' 


Transuranium 
Elements 











La 

57 



Ac 

89 



Ce 

58 



Th 

90 



Pr 

59 



iNd 

eo 



Pa 

91 



u 

92 



Pm 

61 



Np 

93 



Sm 

62'' 



Pu 

94 



Eu 



Al 

95 



Gd 

64 



l 



c 



Tb 



Dy 

66 



Ho 

67 



rl 



Bk 




C»fi 



:S 



Er 

68 



Fm 

inn 



Tm 

59 



Yb 

^0 



Md 

101 



Lu 

7! 



No Lw 






Photoelectric Experiment 



T36 



Photoelectric Experiment 



This transparency can be used to help students visualize the mechanism of the photoelectric effect 

and the method of measuring the stopping voltage. 

Overlay A A schematic diagram is presented of the photoelectric tube connected to a micro- 
ammeter, voltmeter, and a power supply (the empty rectangle above the voltmeter) 
The curved emitter is on the right and the collecting rod is on the left. Note that the 
circuit is open between the emitter and collector. 

Overlay B When the DC power supply provides a positive bias on the collecting rod, the voltmeter 
mdicates this positive potential. Photons of a particular frequency are depicted commg 
in to the emitter. These photons eject photoelectrons whose paths are illustrated by 
arrows. The negative photoelectrons complete the circuit as they accelerate toward the 
positive collector and register a current on the micro-ammeter. Remove this overlay 
and introduce overlay C. 

Overlay C The bias on the collecting rod is now made negative by reversing the terminals on the 
power supply. The voltmeter indicates this reversal. Now as photons eject photoelec- 
trons thev are slightlv repelled by the negative field surrounding the collecting rod. As a 
result only the more energetic photoelectrons get to the collector. The resulting reduc- 
tion in current is shown as a lower reading on the ammeter. Remove this overlay and 
introduce overlay D. 
Overlay D An increased voltage is applied to the collector. When it is sufficiently high it will stop 
all photoelectrons (note zero reading on ammeter). This "stopping ^oltage can be 
used as a measure of the maximum kinetic energy of the photoelectrons. 



T-36 






m 







i 



W 



--^■i 





Current 



Collector Voltage 



T-36 



+ 




A 
B 



Current 



Collector Voltage 



T'36 




A 
C 







■ ' 




■'■4 




;, 


■m 


i 


'W" 


. i 
■Y 


"i^K^'J 


-4 


W; 




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'^^K' 




' iSP^' ' 




'W- 




"®- 



+ 



■ A^ 



Current 



Collector Voltage 



T^BS 




Current 






'. 


1 

i 


i 


"^ 


w 


^ 


^^^»^^ 


4 


■M^'. 



itt 



+ 



Collector Voltage 



j^ Photoelectric Equation 

CO 



"^ 



T37 



Photoelectric Equation 



This transparency will be useful in analyzing data obtained from experiments dealing with stopping 
voltage (see T36). With it you can arrive at the Einstein photoelectric equation. 

Overlay A A plot of typical experimental data on the voltage required between the terminals of a 
vacuum phototube to reduce the tube current to zero. Remove this overlay and in- 
troduce overlay B. 

Overlay B Such data imply that the maximum kinetic energy of the emitted photoelectrons is 
proportional to the frequency of the incident photons. Remove this overlay and 
introduce overlay C. 

Overlay C This shows Einstein's interpretation of the data in terms of a "work function" W, an 
amount of energy that must be supplied to the electrons before they can escape the 
surface. The energy supplied to the electron by the photon is hf, so the emission energy 
KE ^ax = hf- W. 



> 



T-37 



Experimental Data on "Stopping Voltages" 



3 

O 
O 



© 



© 






on 



© 



> 







no emission 



© 



light frequency (f ) 



137 



o 
it 



o 

E 



O 

o 



E 







Inference about Kinetic Energy of Photoelectrons 



B 



no emission 



light frequency (f) 



T-37 



o 
o 










Einstein's Interpretation of Data 



no emission — .*— ► 



maximum KE of 
photoelectron 



energy required 
to escape surface 



light frequency (f) 



Alpha Scattering 



oo 



T38 



Alpha Scattering 



This transparency is useful in discussing Rutherford's alpha particle scattering experiment and in 
contrasting the Thomson and Rutherford models. 

Overlay A A diagrammatic sketch of the Rutherford scattering experiment. A magnifying glass 
(not shown) could be moved around the ZnS screen to detect flashes produced by the 
alpha particles as they strike the screen. 

Overlay B Shows the expected results of the scattering experiment under the assumption that 
matter is composed of Thomson atoms. Note that there is very little deflection. Remove 
this overlay and add overlay C. 

Overlay C These are the results which Rutherford and his co-workers actually observed. The 
large deflections required a completely new explanation of the structure of the atom. 
Remove overlays A and C and introduce overlay D. 

Overlay D Two representations of the Thomson model are shown. The left side depicts large 
(lA diameter) spheres of positive electrification with negative electrons imbedded in 
them "Uke raisins in a muffin". The right side shows a "potential hill" which positive 
alpha particles encounter like marbles rolhng up a slope. Relatisely small deflections 
will be caused by this hill. 

Overlay E The paths of alpha particles would be only slightly deviated as they pass through 
Thomson atoms. 

Overlay F The Rutherford modification on the Thomson model will account for the large de- 
flections actually observed in experiments. The new model contains a very small positive 
nucleus with negative electrons surrounding it. This allows a close approach by alpha 
particles and a consequent large deflection. The "potential hill" model is also adapted 
to a very steep slope (greatly broadened in the diagram) causing sharp deflections the 
closer the particles approach the center. Remove overlays D and E and introduce 
overlay G. 

Overlay G Alpha particle deflections now match observations. 



T-38 



- ■•^>-i," 




Gold 
Foil 



Alpha Particle 
Source 



^Sm.^:'--: 





Zinc Sulfide 
Screen 



ir» 



A 

B 



Results expected 
with Thomson Model 



.^yti-:'- -p;--!^ 



; ' Y-!*-!--! 





■•*^^ 



5^?:. 





Zinc Sulfide 
Screen 



**--<-.i»V,:j..'«v. ;; 



Alpha Particle 
Source 



T'38 



Results obtained 
by Rutherford 



A 

c 



!•■■-■ 





<^o\d^ 







Zinc Sulfide 
Screen 



^ 



Alpha Particle 
Source 



T-38 



\ 






+ 




Thomson Model 



TraasB 



^-scattering 



D 
E 






I 



Thomson Model 



T-38 








+ 




Rutherford Model 



tT^W 



F 

( 




^-scattering 



+ 





Rutherford Model 



Energy Levels — Bohr Theory 



as 



T39 



Energy Levels — Bohr Theory 



This transparency will be useful in relating the Bohr theory of energy levels to the spectrum of hydro- 
gen. It includes a general treatment of the L\man. Balmer and Paschen Series with a more detailed 
coverage of the Balmer Series. 

Overlay A On the left the Bohr orbits for hydrogen are drawn to scale (since the radii should 
increase according to the expression Rn = 0.5 A li-). An energy level diagram is mcluded 
on the right, and a space for spectral Imes across the bottom. Introduce overlays B, 
C and D in order. 

Overlay B Representations of electron quantum "falls" from higher energy levels to the ground 
slate. The resulting emission of the Lyman Series is shown in the spectrum window. 

Overlay C The Balmer Series is produced by excited electrons falling back to the second energy 
level. 

Overlay D The Paschen Series is produced by excited electrons falling back to the third energy 
level. Remove overlays B, C and D. Add the remaining overlays in order. 

Overlay E The Ha line in the Balmer Series is produced by an excited electron falling from the 
third energy level to the second. Note that the scale of the spectral line representation 
has been changed. 

Overlay F The H.j line in the Balmer Series is produced by an excited electron falling from the 
fourth energy level to the second. 

Overlay G The H-, line in the Balmer Series is produced by an excited electron falling from the fifth 
energy level to the second. 

Overlay H The H-, line in the Balmer Series is produced by an excited electron falling from the 
sixth energy level to the second. 

Overlay I The limit of the Balmer Series is approached as excited electrons from energy levels 
higher than /i = 6 fall back to energy level 2. 



T-39 




T=ai 




f49 





r 1 r I F 



♦ 



Lyman Series 



Balmer Series 




ultraviolet 



infrared 



limits of visible range 



ft 



B 





c 
I- 



r«: 






i'y^ 



;>'«'; 









m 

■-V. 



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