• Chem Saver Pg 18

Electrons absorb energy and jump to excited state

Electrons release energy as a photon and fall back to ground state

Chem Saver p 18

Investigation

1. Study the spectrum of the hydrogen atom. Draw lines in the correct part of the spectrum shown below. You will see dozens of lines, but concentrate on the three brightest lines.

R O Y G B i V

H(1e-)

Hydrogen Spectrum1. What is it that causes purple light to be a

different color than red light?2. What is the relationship between the

number of energy levels that an electron falls and the energy of the photon that is emitted when it falls?

3. Why is it that no two elements have the exact same emission spectrum? Click Here for Demonstration

2. The greater the change in energy for an electron, the higher the frequency of the light seen. Red light has the lowest frequency, violet light has the highest frequency, and the other colors have frequencies in between. Match the changes in energy levels shown below with the colored line it represents in the spectrum.

BA

C

Red Line _____

Blue-green Line ____

Violet Line ______A

B

C

3. The red line represents a wavelength of 656 nm, the blue-green line represents a wavelength of 486 nm, and the violet line represents a wavelength of 434 nm. Using the information that 1 m = 1 x 109 nm, convert each of these wavelengths from nanometers to meters.

• Red light = m• Blue-green light = m• Violet light = m

6.56 x 10-7

4.86 x 10-7

4.34 x 10-7

4. Calculate the frequency of each color of light using this equation:

f = c/f = c/,,Frequency = speed of light = 3 x 108 m/s wavelength wavelength

• Frequency of red light ___________ Hz• Frequency of blue-green light _______Hz• Frequency of violet light ___________ Hz

4.57 x 1014

6.17 x 1014

6.91 x 1014

frequency

Speed of light

wavelength

5. Calculate the energy of each color of light using the equation, E = hfE = hf

Energy = 6.63x 10-34 * f • Energy of red light ___________ J• Energy of blue-green light _________J• Energy of violet light ___________ J

3.03 x 10-19

4.09 x 10-19

4.58 x 10-19

Energyfrequency

Planck’s constant

a. Which orbit has the greatest energy?

b. Which orbit has the least energy?

6.

When an electron jumps from E2 to E1, the amount of energy in the light would be E2 - E1 or (–3.4) - (–13.6) = 10.2 units of energy.

7.

• Calculate the amount of energy in the light when an electron jumps from the following energy levels. a) E3 to E1 c) E4 to E2

b) E3 to E2 d) E5 to E2

8. Every possible jump corresponds to light of a different energy. How many different energies of light can be emitted from hydrogen when the electron jumps down to E1 from E2, E3, E4, E5, and E6?

• Is the relationship between Is the relationship between wavelength and frequency a direct or wavelength and frequency a direct or an inverse relationship? an inverse relationship?

InverseInverse

• Is the relationship between energy Is the relationship between energy and frequency a direct or an inverse and frequency a direct or an inverse relationship?relationship?

DirectDirect