lecture11spring2009

lecture11spring2009 - Astronomy100Dr.Rhodes...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Astronomy 100 - Dr. Rhodes Lecture #11 - 2/6/2009
Background image of page 1

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

View Full DocumentRight Arrow Icon
Chapter 4: Light and the Electromagnetic Spectrum The Bohr Model of the Hydrogen Atom The nucleus is the central, massive part of an atom. In the case of hydrogen the nucleus is simply one proton. The electron is the negatively-charged particle that orbits the nucleus of the hydrogen atom. The photon is the smallest possible amount of electromagnetic energy of a particular wavelength. The word photon is the modern term for Planck’s quantum of energy.
Background image of page 2
Chapter 4: Light and the Electromagnetic Spectrum The Bohr Model of the Hydrogen Atom Three postulates of the Bohr atom: 1. The electron travels only in circular orbits around the nucleus. These orbits can have only certain specific energies (i.e most energies are not allowed). 2. An electron in one atom can move from one energy level to another thereby changing the total energy of that atom. 3. The energy of a photon determines the frequency (or wavelength) of light that is associated with that photon.
Background image of page 3

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

View Full DocumentRight Arrow Icon
Properties of the Bohr Model of the Hydrogen Atom
Background image of page 4
Chapter 4: Light and the Electromagnetic Spectrum Energy Levels in the Bohr Atom Each orbit that an electron can occupy is also an energy level for that atom. The smallest orbit in the Bohr Model is called the ground state . It corresponds to the minimum energy for the hydrogen atom. The radius of the ground state is about 1 Angstrom. All orbits larger than the ground state are called excited states ; they all correspond to greater energies than does the ground state.
Background image of page 5

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

View Full DocumentRight Arrow Icon
Chapter 4: Light and the Electromagnetic Spectrum Energy Level Differences in the Bohr Model Since the electron can exist in only a set of discrete energy levels in the Bohr Model, there is also a set of discrete energy differences between those different orbits. Let E 1 be the energy of the ground state and let E 2 be the energy of one of the excited states, then E is the energy difference between those two levels and E=E 2 -E 1 .
Background image of page 6
Examples of Energy Levels in the Hydrogen Atom and Three Different Sets of Excitation Transitions Between These Levels with their Corresponding Wavelengths
Background image of page 7

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

View Full DocumentRight Arrow Icon
Chapter 4: Light and the Electromagnetic Spectrum Excitation of the Bohr Atom Since each larger electron orbit corresponds to a larger amount of energy for the atom, energy must be supplied to an atom before the electron can be moved from the ground state to one of the excited states. The process of moving an electron outward to a larger orbit is excitation . The energy necessary to excite an atom can be supplied by a photon passing by the atom if that photon has just the right energy
Background image of page 8
Chapter 4: Light and the Electromagnetic Spectrum Excitation of Atoms and Absorption of Light When a photon supplies the energy necessary to excite an atom, the energy of the photon is destroyed in the process. The photon is said to
Background image of page 9

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

View Full DocumentRight Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 37

lecture11spring2009 - Astronomy100Dr.Rhodes...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online