Per3_exercise - Period 3 Exercise Answers E.1 An electron...

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Period 3 Exercise Answers E.1 An electron absorbs a photon that has 5.0 x 10 –21 joules of energy and the electron moves to a higher energy level. The electron later drops to a lower energy level and emits a photon that has 3.3 x 10 –22 joules of energy. How much more energy must be emitted to satisfy conservation of energy? a) 1.7 x 10 –22 joules b) 4.7 x 10 –22 joules c) 1.7 x 10 –21 joules d) 4.7 x 10 –21 joules e) 4.7 x 10 –20 joules The total energy emitted by the electron must equal the total energy absorbed. Subtract to find the difference between the energy absorbed and the energy emitted. When adding or subtracting numbers in scientific notation, each term must have the same power of ten. 5.0 x 10 –21 J 5.0 x 10 –21 J – 3.3 x 10 –22 J = – 0. 33 x 10 –21 J 4.7 x 10 –21 J Or 5.0 x 10 –21 J 50.0 x 10 –22 J – 3.3 x 10 –22 J = – 3. 3 x 10 –22 J 46.7 x 10 –22 J = 4.7 x 10 –21 J E.1 = d
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E.2 The part of the electromagnetic spectrum that causes tanning is
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Per3_exercise - Period 3 Exercise Answers E.1 An electron...

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