Chapter 6 - Electronic Structure of Atoms

# Chapter 6 - Electronic Structure of Atoms - Chapter 6...

This preview shows pages 1–8. Sign up to view the full content.

1 Chapter 6: Chapter 6: Electronic Structure Electronic Structure of Atoms of Atoms Waves Waves • To understand the electronic structure of atoms, one must understand the nature of electromagnetic radiation. • The distance between corresponding points on adjacent waves is the wavelength ( λ ) .

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

View Full Document
2 Waves Waves • The number of waves passing a given point per unit of time is the frequency ( ν ) . • For waves traveling at the same velocity, the longer the wavelength, the smaller the frequency. Electromagnetic Radiation Electromagnetic Radiation • All electromagnetic radiation travels at the same velocity in a vacuum: the speed of light ( c ), c = 3.00 × 10 8 m/s . • The speed of a wave is the product of its wavelength ( λ ) and frequency ( ). c = λν • If either the wavelength or frequency is known, the other can be calculated.
3 The Nature of Energy The Nature of Energy • The wave nature of light does not explain how an object can glow when its temperature increases. • Max Planck explained it by assuming that energy comes in packets called quanta . •The se quan ta we re assumed to be absorbed or emitted by matter. The Nature of Energy The Nature of Energy • Einstein used this assumption to explain the photoelectric effect. • He concluded that energy is proportional to frequency: E = h ν where h is Planck’s constant, 6.63 × 10 34 J·s. PhotoelectricEffect.MOV

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

View Full Document
4 The Nature of Energy The Nature of Energy • Therefore, if one knows the wavelength of light, one can calculate the energy in one photon, or packet, of that light: c = λν E = h ν The Nature of Energy The Nature of Energy Another mystery involved the emission spectra observed from energy emitted by atoms and molecules.
5 The Nature of Energy The Nature of Energy •One does no t observe a continuous spectrum, as one gets from a white light source. •On ly a line spectrum of discrete wavelengths is observed. The Nature of Energy The Nature of Energy • Niels Bohr adopted Planck’s assumption and explained these phenomena in this way: 1. Electrons in an atom can only occupy certain orbits (corresponding to certain energies).

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

View Full Document
6 The Nature of Energy The Nature of Energy • Niels Bohr adopted Planck’s assumption and explained these phenomena in this way: 2. Electrons in permitted orbits have specific, “allowed” energies; these energies will not be radiated from the atom. The Nature of Energy The Nature of Energy • Niels Bohr adopted Planck’s assumption and explained these phenomena in this way: 3. Energy is only absorbed or emitted in such a way as to move an electron from one “allowed” energy state to another; the energy is defined by E = h ν
7 The Nature of Energy The Nature of Energy The energy absorbed or emitted from the process of electron promotion or demotion can be calculated by the equation: Δ E = R H ( ) 1 n f 2 1 n i 2 - where R H is the Rydberg constant, 2.18 × 10 18 J, and n i and n f are the initial and final energy levels of the electron.

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 27

Chapter 6 - Electronic Structure of Atoms - Chapter 6...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online