Chapter7-1

Chapter7-1

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Unformatted text preview: f 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.

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