Unit 8 Quiz--Bohr's Model of the Atom |

__Multiple Choice__ (Choose the best answer.)

- To understand Bohr's model of the atom, you need to understand how light can be thought of as energy that travels
in a wave. Which of the following statements about the wave nature of light are true?
The wavelength is equal to the number of waves that pass a given point in one second.

The symbol for wavelength is .

Frequency can be measured in Hertz, 1/s, waves/s, or s

^{-1}.As the wavelength gets larger, the frequency gets larger.

The speed of light in a vacuum is 3.00 x 10

^{8}cm / s.

- Fifteen waves pass a point in 4.0 seconds. What is the freqency of the wave?
0.17 Hz

0.27 Hz

3.8 Hz

60. Hz

None of these are correct.

- A typical microwave has a wavelength equal to 0.10 cm. What is the frequency of such a wave? (The speed of
light "c" = 3.00 x 10
^{10}cm / s.)3.0 x 10

^{11}s^{-1}3.0 x 10

^{9}s^{-1}3.3 x 10

^{-10}s^{-1}3.3 x 10

^{-12}s^{-1}None of these are correct.

- A typical ultraviolet wave has a frequency of 5.0 x 10
^{16}waves / sec. What is the wavelength of such a wave?1.7 x 10

^{8}cm1.7x 10

^{6}cm6.0 x 10

^{-7}cm6.0 x 10

^{-9}cmNone of these area correct.

- How much energy would a photon of light described in problem 4) possess? (Planck's Constant , h = 6.63 x 10
^{-34}J * s ).3.3 x 10

^{-17}J3.0 x 10

^{-16}J4.0 x 10

^{-40}J4.0 x 10

^{-18}JNone of these are correct.

- Bohr's Model of the atom included the idea(s) that:
The electron can have only certain energies, including a lowest-level ground state.

Electrons absorb energy by moving to higher energy orbits.

Electrons emit energy as light when they move to lower energy orbits.

B and C are correct.

A, B, and C are correct.

The diagram at right depicts the energy levels present in the hydrogen atom as envisioned by Bohr. The bottom right corner of the digram is the nucleus of the H atom. The numbered orbits refer to the allowed energy levels in the atom. Use this diagram to answer questions 7 - 10 below.

- How much energy would be released as an electron moved from the n = 4 to the n = 3 energy level?
2.043 x 10

^{-18}J3.981 x 10

^{-18}J1.938 x 10

^{-18}J1.050 x 10

^{-19}JNone of these are correct because energy is

*absorbed*.

- What frequency of light would be emitted in the electron transition mentioned in question 7?
1.58 x 10

^{14}Hz6.31 x 10

^{-15}Hz1.89 x 10

^{-4}Hz9.96 x 10

^{-53}HzNone of these are correct.

- What would be the wavelength of light emitted in question 7?
1.58 x 10

^{14}cm6.31 x 10

^{-15}cm1.89 x 10

^{-4}cm9.96 x 10

^{-53}cmNone of these are correct.

- What type of light would be emitted in question 7? (Use the electromagnetic spectrum as shown in figure 13.10
on page 373 of your text. There are 1 x 10
^{-7}cm in 1 nm.)Ultraviolet

Infrared

Visible Light

X-Rays

Radio Waves

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