Electrons in atoms
This presentation is the property of its rightful owner.
Sponsored Links
1 / 14

II. Bohr Model of the Atom PowerPoint PPT Presentation


  • 75 Views
  • Uploaded on
  • Presentation posted in: General

Electrons in Atoms. II. Bohr Model of the Atom. A. Bohr Model. Niels Henrik David Bohr 1885 - 1962 Born 1885, Copenhagen, Denmark. Father was an eminent physiologist. 1911 - Studied and worked at Cambridge under Sir JJ Thomson

Download Presentation

II. Bohr Model of the Atom

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Electrons in atoms

Electrons in Atoms

II. Bohr Model of the Atom


A bohr model

A. Bohr Model

  • NielsHenrik David Bohr 1885 - 1962

    • Born 1885, Copenhagen, Denmark.

    • Father was an eminent physiologist.

    • 1911 - Studied and worked at Cambridge under Sir JJ Thomson

    • 1912 – worked in Ernest Rutherford’s lab in Manchester, England.

    • 1922 – Nobel Prize in Physics for work on the structure of atoms.


A bohr model1

A. Bohr Model

  • e- exist only in orbits with specific amounts of energy called energy levels

  • Therefore…

    • e- can only gain or lose certain amounts of energy

    • only certain photons are produced


B line emission spectrum

B. Line-Emission Spectrum

excited state

ENERGY IN

PHOTON OUT

ground state


B line emission spectrum1

Energy of photon depends on the difference in energy levels

Bohr’s calculated energies matched the IR, visible, and UV lines for the H atom

B. Line-Emission Spectrum

6

5

4

3

2

1


B line emission spectrum2

B. Line-Emission Spectrum

  • Each element has a unique bright-line emission spectrum.

    • “Atomic Fingerprint”

Helium

  • Bohr’s calculations only worked for hydrogen! 


Electrons in atoms1

Electrons in Atoms

III. Quantum Model of the Atom


A electrons as waves

A. Electrons as Waves

  • Louis de Broglie (1924)

    • Applied wave-particle theory to e-

    • e- exhibit wave properties

QUANTIZED WAVELENGTHS


A electrons as waves1

VISIBLE LIGHT

ELECTRONS

A. Electrons as Waves

EVIDENCE: DIFFRACTION PATTERNS


B quantum mechanics

B. Quantum Mechanics

  • Heisenberg Uncertainty Principle

    • Impossible to know both the velocity and position of an electron at the same time


B quantum mechanics1

B. Quantum Mechanics

  • SchrödingerWave Equation (1926)

    • finite # of solutions  quantized energy levels

    • defines probability of finding an e-


B quantum mechanics2

Radial Distribution Curve

Orbital

B. Quantum Mechanics

  • Orbital (“electron cloud”)

    • Region in space where there is 90% probability of finding an e-


B quantum mechanics3

B. Quantum Mechanics

  • Summary of Quantum Theory

    • Describes mathematically the wavelike properties of e-1 and other small particles.

    • Applies to ALL atoms (unlike the Bohr model)

    • Supports the idea that e-1 exist in regions called orbitals where there is a probability of finding them.

    • Ask me about the 4th bullet point


B quantum mechanics4

B. Quantum Mechanics

  • Organization of electrons in atoms

    • Energy levels

    • Sublevels

    • Orbitals


  • Login