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orbitals: l=0 l=1 l=2 l=3
n=1
n=2
n=3
n=4 1s
2s
3s
4s 2p
3p
4p Total # of
orbitals
1
1+3=4 3d
4d 1+3+5=9 4f 1+3+5+7=16 ANSWER: 16
54
Chem 6A Michael J. Sailor, UC San Diego Weds, Oct 27 55
Chem 6A Michael J. Sailor, UC San Diego Weds, Oct 27
• Quiz 6 on Friday Oct 29 covers material
through Fri Oct 22 lecture, and problem
7.35 in the homework 55
Chem 6A Michael J. Sailor, UC San Diego Weds, Oct 27
• Quiz 6 on Friday Oct 29 covers material
through Fri Oct 22 lecture, and problem
7.35 in the homework
• Special bonus if you come in costume to
class on Oct 29 55
Chem 6A Michael J. Sailor, UC San Diego Problem: Energy of electronic transitions
One of the emission lines from the star σ Ori AB in
the constellation Orion occurs at a wavelength of
486.3 nm. The line arises from atomic hydrogen
contained in that star. This line probably
corresponds to the following electronic transition: a) n=5 to n=1 b) n=4 to n=1 c) n=3 to n=1 d) n=4 to n=2 e) n=5 to n=2
56
Chem 6A Michael J. Sailor, UC San Diego 57
Chem 6A Michael J. Sailor, UC San Diego Solution: Energy of electronic transitions
Another way to solve this problem: Assume n1 = 1, calculate the
value of n2 given that λ= 486.3 nm 1
1
1
= RH 2 − 2 λ n1 n 2 1 1 1
1
= R H − 2 = R H 1 − 2 λ
1 n2 n2 €
Rearranging, 1
1
1−
=2
λ ⋅ RH n2
Chem 6A Michael J. Sailor, UC San Diego 58 Solution: Energy of electronic transitions
1
1
1−
=2
λ ⋅ RH n2
Solve for n2:
−1/ 2 1
n2 =
= 1 − 1 λ ⋅ RH €
1 − λ ⋅ RH −1/ 2 1
= 1.1
n 2 = 1 −
−2 486.3 ⋅ 1.097 × 10 1 59 Chem 6A Michael J. Sailor, UC San Diego Solution: Energy of electronic transitions
1.1 is not a valid quantum number! Assume that n1 = 2 1
1 1 1
1
= RH 2 − 2 = RH − 2 λ
n2 2 4 n2 Solve for n2: −1/ 2 1
1
= −
n2 =
1 4 λ ⋅ RH 1 − 4 λ ⋅ RH 1 −1/ 2 1
n 2 = 0.25 −
−2 486.3 ⋅ 1.097 × 10 Chem 6A Michael J. Sailor, UC San Diego = 3.998 = 4
60 Solution: Energy of electronic transitions
So the transition is n = 4 to n = 2; the
answer is (d): a) n=5 to n=1 b) n=4 to n=1 c) n=3 to n=1 d) n=4 to n=2 e) n=5 to n=2 61
Chem 6A Michael J. Sailor, UC San Diego Quantum dots: Artiﬁcial atoms
http://www.invitrogen.co...
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This note was uploaded on 08/31/2011 for the course CHEM 6A taught by Professor Pomeroy during the Winter '08 term at UCSD.
 Winter '08
 Pomeroy

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