Esp/aew Chemistry I

Academic Excellence Workshop ☻ Chemistry I ☻ September 28th ☻ Problem set 2 1. True or False: Neutral copper is diamagnetic. 2. True or False: An atom with unpaired electrons is paramagnetic. 3. True or False: The effective nuclear charge is the number of protons – electrons 4. True or False: The number of angular nodes is equal to the quantum number (l). 5. True or False: If a proton and an electron have the same velocity, the DeBroglie Wavelength of the electron is larger. 6. True or False: Effective nuclear charge is the most important reason that sodium atom is larger than a lithium atom. 7. True or False: A 5p orbital has fewer radial nodes than does a 4p orbital. 8. True or False: A 5f orbital has fewer angular nodes than does a 5p orbital. 9. What wavelength of light is emitted when an electron on a hydrogen atom going from energy level 4 to 1? Useful information Rydberg Constant = 1.097x107 m-1 1/ = RH(1/n12-1/n22) (a) 10 Mm (b) 97 m (c) 102 nm (d) 87 nm (e) None of the above

10. Sketch shapes of s, p, and d orbitals and indicate where the angular nodes are for each one.

11. X-rays with a wavelength of 1.54 x 10-10 m are produced when a copper metal target is bombarded with high energy electrons that have been accelerated by a voltage difference of 30,000 V. The kinetic energy of the electrons equals the product of the voltage difference and the electronic charge in coulombs, where 1 volt-coulomb = 1 J. The mass of an electron is 9.11 x 10-31 kg and the charge on one electron is 1.602 x 10-19 C. What is the wavelength (in meters) of one of the high energy electrons? How quickly is one of these electrons moving? Hint:

Kinetic energy = (1/2 mv2)

12. a. Using the Slater rules, determine the effective nuclear charge on a valence electron of elemental sulfur.

b. How does this compare to the effective nuclear charge on a valence electron of sulfide (S-2)?

c. How does Zeff of S-2 compare to the effective nuclear charge on a valence electron of elemental Neon?

13. Which of the following has exactly four valence electrons? (a) Al (b) Ca+2 (c) S-2 (d) Cr (e) None of the above 14. Which of the following has the largest first ionization energy? (a) Mg (b) B (c) Se (d) Cl (e) F 15. Which of the following is the largest atom? (a) Rb (b) Rb+ (c) Sr+2 (d) Br(e) All the same 16. Which of the following is the smallest atom? (a) Rb (b) Rb+ (c) Sr+2 (d) Br(e) All the same 17. Hypothetical Universe question: if quantum legal numbers were changed so that l = 0, 1, … n instead of the typically upper limit l = 0, 1, 2 … n-1, how many unpaired electrons would be in sulfur? (a) 2 (b) 1 (c) 4 (d) 6 (e) None of the above