Atomic Structure
The University of the West Indies (Mona)
Department of Chemistry
Preliminary Chemistry A (Chem 0901)
Atomic Structure: Tutorial 2
For discussion in the week beginning September 24, 2012.
Answers should be submitted by 9:00 am on Monday September 24, 2012 in the box provided.
Please write your ID number and Laboratory day clearly on your script. 1. Give an expression for the Balmer-Rydberg equation in terms of wavelength λ, the Rydberg constant R, and the integers m and n where m < n. [3] a. Using the equation calculate the wavelength (in nanometers) of the first line of the Lyman series (m = 1). [3] b. To which region of the electromagnetic spectrum does this wavelength correspond ? [1] c. Using the Balmer-Rydberg equation, at what value of n does the red line (wavelength = 656.3 nm) in the Balmer series of the hydrogen emission spectrum occur. [5] 2. Calculate the wavelength of the following: a. A photon of energy 2.89 x 10-19 J [2] b. An electron travelling at 1/5 of the speed of light [3] c. A 70 kg man running a 100 m sprint in 9.84 s. [3] i. In parts b. and c., how does the wavelength compare to the region in which the “particle” is confined? [2] ii. Based on your answer in part c, how significant is the man’s wave-like properties? Briefly explain. [1] 3. Write the expression for the Heisenberg Uncertainty Principle (HUP). [2] a. Determine the uncertainty in the path of flight of an 8.040 g bullet if its velocity is 360 ± 1 ms-1. (Hint: the mass is known with high precision therefore Δmv = mΔv) [3] b. Determine the uncertainty in the position of an electron if the velocity is 5.80 ± 0.02 × 106 ms-1. (Use the hint given above) [3] i. How does the error in the position of the “particles” in a. and b. compare to the space they occupy? [2] 4. For an electron of principal
Department of Chemistry
Preliminary Chemistry A (Chem 0901)
Atomic Structure: Tutorial 2
For discussion in the week beginning September 24, 2012.
Answers should be submitted by 9:00 am on Monday September 24, 2012 in the box provided.
Please write your ID number and Laboratory day clearly on your script. 1. Give an expression for the Balmer-Rydberg equation in terms of wavelength λ, the Rydberg constant R, and the integers m and n where m < n. [3] a. Using the equation calculate the wavelength (in nanometers) of the first line of the Lyman series (m = 1). [3] b. To which region of the electromagnetic spectrum does this wavelength correspond ? [1] c. Using the Balmer-Rydberg equation, at what value of n does the red line (wavelength = 656.3 nm) in the Balmer series of the hydrogen emission spectrum occur. [5] 2. Calculate the wavelength of the following: a. A photon of energy 2.89 x 10-19 J [2] b. An electron travelling at 1/5 of the speed of light [3] c. A 70 kg man running a 100 m sprint in 9.84 s. [3] i. In parts b. and c., how does the wavelength compare to the region in which the “particle” is confined? [2] ii. Based on your answer in part c, how significant is the man’s wave-like properties? Briefly explain. [1] 3. Write the expression for the Heisenberg Uncertainty Principle (HUP). [2] a. Determine the uncertainty in the path of flight of an 8.040 g bullet if its velocity is 360 ± 1 ms-1. (Hint: the mass is known with high precision therefore Δmv = mΔv) [3] b. Determine the uncertainty in the position of an electron if the velocity is 5.80 ± 0.02 × 106 ms-1. (Use the hint given above) [3] i. How does the error in the position of the “particles” in a. and b. compare to the space they occupy? [2] 4. For an electron of principal