CHAPTER 5: ELECTRONS IN ATOMS • Rutherford’s model of the atom did not explain how the electrons occupy the space surrounding the nucleus. Recall: • In the early 1900’s, investigations using the relationships that exist between light and electrons will reveal a more accurate model of the atom. Model of The Atom Opposites attract….right??
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CHAPTER 5: ELECTRONS IN ATOMS Rutherford’s model of the atom did not explain how the electrons occupy the space surrounding the nucleus. Recall: In the.
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CHAPTER 5: ELECTRONS IN ATOMS
• Rutherford’s model of the atom did not explain how the electrons occupy the space surrounding the nucleus.
Recall:
• In the early 1900’s, investigations using the relationships that exist between light and electrons will reveal a more accurate model of the atom.
Determine the electron configuration for the following elements:
Lithium 3 electrons
1s22s1
Nitrogen 7 electrons
1s22s22p3
Neon 10 electrons
1s22s22p6
In order to write a noble gas notation simply include the previous noble gas (in brackets) and list the electron configuration from the next element from the noble gas to the element you are determining the configuration for.
Write the noble gas notation for Sodium
[Ne]3s¹
Write the noble gas notation for Sulfur
[Ne]3s²3p⁴
Noble Gas Notation
• in order to write long configurations much easier we can use a noble gas configuration.
Properties of Light
• Light behaves both as a wave and a particle.
Light’s Wavelike Properties
• visible light is one kind of electromagnetic radiation.
• all electromagnetic radiation moves at the speed of light (3.00 x 108 m/s)
Properties of Waves
1. Wavelength: () the distance between corresponding points on adjacent waves.
2. Frequency: () the number of waves that pass a given point in one second.
• Frequency is measured in Hertz (Hz).
Speed of Light Equation
What is the wavelength of radiation with a frequency of1.5 x 1013 Hz?
Wavelength x 1.50 x 1013Hz = 3.00 x 108m/s
Wavelength = 3.00 x 108m/s / 1.50 x 1013Hz
Wavelength = 2.00 x 10-5m
The Photoelectric Effect
• a phenomena involved with the emission of electrons from a metal when light shines on a metal.
• light of only a certain frequency enabled this event to occur light behaves like streams of particles!
PhotoelectricEffectMax Planck
• suggested that energy could only exist in discrete lumps called quantum.
E = h
h = 6.626 x 10-34 JsPlanck andBlackbody Radiation
Einstein also proposed that light delivers its energy in chunks called photons.
Therefore, in order for an electron to be ejected (photoelectric effect) , the electron must be struck by a single photon, of certain energy, to knock the electron loose.