(Solution Manual, There is no Solution for Chapter 1)
CHAPTER 2: ATOMIC STRUCTURE
h 6.626 10 34 J s
2.1 a. = = 2.426 10 11 m
mv (9.110 10 –31kg) (0.1) (2.998 108 m s –1 )
h 6.626 1034 J s
b. = = 6 10 34 m
mv 0.400 kg (10 km/hr 10 m/km 1hr/3600s)
3
h 6.626 10 34 J s
c. = = -1 9.1 10
35
m
mv 8.0 lb 0.4536 kg/lb 2.0 m s
h 6.626 10 34 J s
d. = =
mv 13.7 g kg/10 3 g 30.0 mi hr -1 1 hr/3600s 1609.3 m/mi
3.61 10 33 m
1 1 hc 1
2.2 E RH 2 – 2 ; RH 1.097 10 7 m–1 1.097 10 5 cm–1 ;
2 nh E __
1 1 12
nh 4 E RH – RH 20,570cm –1 4.085 10 –19 J
4 16 64
4.862 10 –5 cm = 486.2 nm
1 1 21
nh 5 E RH – RH 23,040cm –1 4.577 10 –19 J ;
4 25 100
4.34110 –5 cm = 434.1 nm
1 1 8
nh 6 E RH – RH 24,380cm –1 4.841 10 –19 J ;
4 36 36
4.102 10 –5 cm = 410.2 nm
1 1 45
2.3 E RH
4 – RH 25,190cm–1 5.002 10 –19 J
49
196
1
__ 3.970 10 –5 cm = 397.0 nm
hc (6.626 1034 J s)(2.998 108 m/s)
2.4 383.65 nm E 5.178 1019 J
(383.65 nm)(m/10 nm)9
hc(6.626 10 34 J s)(2.998 108 m/s)
379.90 nm E 5.229 10 19 J
(379.90 nm)(m/10 nm) 9
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,2 Chapter 2 Atomic Structure
1
1 1 1 1 E 1 E 2
E RH 2 2 ; and nh
2 nh nh
2
4 RH 4 RH
1
1 5.178 10 19 J 2
For 383.65 nm: nh 18
9
4 2.1787 10 J
1
1 5.229 10 19 J 2
For 379.90 nm: nh 18
10
4 2.1787 10 J
2.5 The least energy would be for electrons falling from the n = 4 to the n = 3 level:
1 1 7
E RH 2 2 2.1787 10 18 J 1.059 10 19 J
3 4 144
The energy of the electromagnetic radiation emitted in this transition is too low for
humans to see, in the infrared region of the spectrum.
2.6
E 102823.8530211 cm 1 97492.221701 cm 1 5331.6313201 cm 1
E hc (6.626 1034 J s)(2.998 108 m s)(100cm m)(5331.6313201 cm 1 )
E 1.059 1019 J
This is the same difference found via the Balmer equation in Problem 2.5 for
a transition from n 4 to n 3. The Balmer equation does work well for hydrogen.
2.7 a. We begin by symbolically determining the ratio of these Rydberg constants:
2 2 He + (Z He+ )2 e4 2 2 H (Z H )2 e4
RHe + RH
(4 0 )2 h2 (4 0 )2 h2
RHe + He+ (Z He+ )2 4 He+
(since Z 2 for He )
RH H (Z H ) 2 H
The reduced masses are required (in terms of atomic mass units):
1 1 1 1 1
H me m proton 5.4857990946 10 m 1.007276466812 mu
4
u
1
1823.88 mu1; H 5.482813 104 mu
H
1 1 1 1 1
He me mHe2 5.4857990946 10 m 4.001506179125 mu
4
u
1
1823.13 mu1; He + 5.485047 10 4 mu
He +
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, Chapter 2 Atomic Structure 3
The ratio of Rydberg constants can now be calculated:
RHe+ 4 He+ 4(5.485047 104 mu )
4.0016
RH H 5.482813 104 mu
b. RHe + 4.0016RH (4.0016)(2.1787 1018 J) 8.7184 1018 J
c. The energy difference is first converted to Joules:
E hc (6.626 1034 J s)(2.998 108 m s)(100cm m)(329179.76197 cm 1 )
E 6.5391 1018 J
The Rydberg equation is applied, affording nearly the identical Rydberg constant for He+:
1 1 1 1
E RHe + ( 2 2 ) 6.5391 1018 J RHe + ( )
n n 1 4
l h
RHe + 8.7188 1018 J
h2 2
2.8 a. – E ; A sin rx B cos sx
8 2 m x 2
= Ar cos rx – Bs sin sx
x
2
= –Ar 2 sin rx – Bs 2 cos sx
x 2
h2
–
8 m
– Ar
2
2
sin rx – Bs2 cos sx E A sin rx + B cos sx
If this is true, then the coefficients of the sine and cosine terms must be independently
equal:
h 2 Ar 2 h 2 Bs 2
EA ; = EB
8 2 m 8 2 m
8 2 mE 2
r 2 s2 ; r s 2mE
h 2
h
b. A sin rx ; when x 0, A sin 0 0
when x a, A sin ra 0
n
ra n ; r
a
r 2 h 2 n 2 2 h 2 n 2h 2
c. E
8 2 m a 2 8 2 m 8ma 2
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, 4 Chapter 2 Atomic Structure
a a a
x
2 n a nx nx
d. dx
2 2
A sin dx A
2
sin 2 d
a n a a
0 0 0
a
a 2 1 nx 1 2nx
A – sin 1
n 2 a 4 a 0
aA 2 1 na 1 1
– sin2n – 0 sin0 1
n 2 a 4 4
2
A
a
2.9 a. 3pz 4dxz
b. 3pz 4dxz
c. 3pz 4dxz
For contour map, see Figure 2.8.
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