Fireworks and Electrons

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Fireworks and Electrons

• Light and electrons

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Violet Color
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Green Color
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How it Works

• Fireworks work by a three-step process. First,
  an exothermic reaction (for example, the
  combustion of gunpowder) is used to provide
  energy.

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How it Works
Second, the energy released in the
exothermic reaction excites electrons in metal
ions. Third, light is emitted when these
electrons relax back to the ground state. Since
the energy ofelectrons is quantized, each metal
emits characteristic colors of light.
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Our Experiment

• When a balloon containing hydrogen gas and
• potassium carbonate is ignited, violet light is
• emitted. Potassium emits violet light when its
• electrons return from an excited state to the
  ground
• state.

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Characteristics of Electrons

• Extremely small mass
• Located outside the nucleus
• Moving at extremely high speeds in a sphere
• Have specific energy levels

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Energy of Electrons

• When atoms are heated, bright lines appear called
  line spectra
• Electrons in atoms arranged in discrete levels.
• An electron absorbs energy to jump to a higher
  energy level.
• When an electron falls to a lower energy level,
  energy is emitted.

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Loss and Gain of Energy

Loss
G a I n
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Clicker Check EA1

• Answer with
• 1) Energy absorbed 2) Energy emitted
• 3) No change in energy
• A. What energy change takes place when an
  electron in a hydrogen atom moves from the first
  (n1) to the second shell (n2)?

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Clicker Check

• What energy change takes place when the electron
  moves from the third shell to the second shell?

Answer with 1) Energy absorbed 2) Energy
emitted 3) No change in energy
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• What metal nitrate is present in solution 1?a)
  Cu b) K c) Ca

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Clicker Check

• What metal nitrate is present in solution 2?a)
  Cu b) K c) Ca