{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

notes_Lecture_17_111210

# notes_Lecture_17_111210 - Lecture 17 Quantum Mechanics...

This preview shows pages 1–9. Sign up to view the full content.

Lecture 17: Quantum Mechanics Reading: Zumdahl 12.5 & 12.6 Problems for Extra Practice – 47, 49 (Chapter 12) Outline – Bohr’s Model of the hydrogen atom (12.4) – Quantum-Mechanical model of the atom (12.5) – The particle in a box (12.6) – The wave equation for the hydrogen atom (12.7)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Emission spectrum of H We can use the emission spectrum to determine the energy levels for the hydrogen atom. The emitted photon shows up as one of the lines in the spectrum... …but it represents a change between two energy levels in the atom. Δ E = hc/ λ barb2right λ = hc/ Δ E If λ = 440 nm, ΔΕ = 4.5 x 10 -19 J
The Balmer Model Joseph Balmer (1885) first noticed that the frequency of visible lines in the H atom spectrum could be reproduced by: ... 5 , 4 , 3 1 2 1 2 2 = - n n ν The above equation predicts that as n increases, the frequencies become more closely spaced. Empirical!!!

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
The Rydberg Model Johann Rydberg extends the Balmer model by finding more emission lines outside the visible region of the spectrum: - = 2 2 2 1 1 1 n n R y ν This suggests that the energy levels of the H atom are proportional to 1/n 2 Niels Bohr uses the emission spectrum of hydrogen to develop a quantum model for H… ... 3 , 2 , 1 1 = n ... , 2 , 1 1 1 2 + + = n n n 1 15 10 29 . 3 - × = s R y Empirical!!!
Bohr’s Model of the H Atom × - = - 2 2 18 J 10 178 . 2 n Z E Z = atomic number (1 for H) n = integer (1, 2, ….) Energy levels get closer together as n increases. At n = infinity ( ), E = 0…no interaction between nucleus and electron. Electron circles the nucleus in only certain allowed circular orbits. Orbit energies are quantized, and described according to:

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Identify the energy level diagram that best represents the H atom: A B C D
The Bohr Model (cont.) We can use the Bohr model to predict what Δ E is for any two energy levels (we can predict the photon λ ) Δ E = E final - E initial ( ) × - - × - = - - 2 2 18 2 2 18 1 ) (Z J 10 178 . 2 1 ) J(Z 10 178 . 2 initial final n n - × - = - 2 2 2 18 1 1 ) J(Z 10 178 . 2 initial final n n

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
The Bohr Model (cont.) Example: At what wavelength will emission from n = 4 to n = 1 for the H atom be observed?
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 25

notes_Lecture_17_111210 - Lecture 17 Quantum Mechanics...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online