1. Unit 4 – Electrons
Exam Review

2. 1. What is the next atomic orbital in the series: 1s, 2s, 2p, 3s, 3p, ?
A. 3d
B. 4s
C. 4p
D. 3f

3. 2. In Bohr’s model of the atom, where are the electrons. A
2. In Bohr’s model of the atom, where are the electrons? A. Evenly throughout the entire atom. B. In orbitals. C. In orbits. D. His model did not include electrons.

4. 3. How does the energy of an electron change when the electron moves closer to the nucleus? A. increases B. decreases C. remains the same

5. 4. If the spin of one electron in an orbital is “clockwise”, what is the spin of the other electron in that orbital? A. clockwise B. counterclockwise C. it doesn’t spin because the cancel each other D. towards the nucleus

6. 5. What is the approximate energy of a photon having a frequency of 4
5. What is the approximate energy of a photon having a frequency of 4.0 x 1015 Hz? (h = 6.63 x J . s) A. 1.7 x J B x J C x J D. 2.7 x J

7. Which of the following would be most stable:
A. 4d5
B. 4d4
C. 4d10
D. 4f6

8. 7. How many unpaired electrons are in a sulfur atom (Z = 16). A. 4 B
7. How many unpaired electrons are in a sulfur atom (Z = 16)? A. 4 B. 1 C. 2 D. 0

9. 8. According to the Heisenberg uncertainty principle, if the position of a moving particle is known, what other quantity CANNOT be known? A. energy B. velocity C. mass D. none of the above

10. Which of the following has the highest frequency:
A. x-rays
B. gamma rays
C. radio waves
D. UV rays

11. 10. What is the electron configuration of potassium. A. [Ar]4s1 B
10. What is the electron configuration of potassium? A. [Ar]4s1 B. [Ne]4s1 C. 1s12s12p63p6 D. 1s22p63s23p64s1

12. 11. What is the number of electrons in the outermost energy level of an oxygen atom? A. 4 B. 6 C. 8 D. 10

13. 12. How does the speed of visible light compare with the speed of gamma rays, when both speeds are measured in a vacuum? A. slower B. faster C. the same D. you can’t compare them

14. 13. The principal quantum number indicates what property of an electron? A. the energy level of the electron B. the spin of the electron C. the sublevel of the electron D. the shape of the orbital

15. 14. Which scientist developed the quantum mechanical model of the atom
14. Which scientist developed the quantum mechanical model of the atom? A. Bohr B. Heisenberg C. de Broglie D. Schrödinger

16. 15. What is the maximum number of electrons in the second principal energy level? A. 2 B. 8 C. 18 D. 32

17. 16. If three electrons are available to fill three empty 2p atomic orbitals, how will the electrons be distributed? A. All in one orbital B. 2 of them will be in one orbital; 1 in another C. 1 electron in each orbital D. they can’t all fit in the 2p orbitals

18. 17. What is the wavelength of a wave that has a frequency of 60. MHz? A. 5.0 x 106 m B. 5.0 m C. 5.0 x 103 m D. 5.0 x 10-1 m

19. 18. When an electron moves from a lower to a higher energy level, the electron _____. A. must give off a photon of energy B. must absorb a photon of energy C. must slow down D. must stay in the same position

20. 19. According to the aufbau principle, electrons enter orbitals of ___ first. A. lowest energy B. highest energy C. lowest monemtum D. highest momentum

21. 20. What is the maximum number of “f” orbitals in any single energy level of an atom? A. 1 B. 3 C. 5 D. 7

22. 21. What types of atomic orbitals (s, p, d, or f) are in the third principal energy level? A. s and p B. s, p, and f C. s, p, and d D. s, p, d, and f

23. 22. How would the atomic emission spectra of a sodium atom on Earth compare with sodium in the sun? A. it would be the same B. it would be different C. you can’t compare the two D. sodium doesn’t have an emission spectra

24. 23. How many energy sublevels are in the second principal energy level
23. How many energy sublevels are in the second principal energy level? A. 1 B. 2 C. 3 D. 4

25. 24. Emission of light from an atom occurs when an electron _____. A
24. Emission of light from an atom occurs when an electron _____. A. moves from a lower to higher energy level B. moves from a higher to lower energy level C. releases a photon D. both b and c

26. 25. Who predicted that all matter can behave as waves as well as particles? A. Bohr B. Schrödinger C. de Broglie D. Plank

27. 26. What are quanta of light called. A. quantums B. photons C
26. What are quanta of light called? A. quantums B. photons C. electrons D. radiation

28. 27. Stable electron configurations are likely to contain ____. A
27. Stable electron configurations are likely to contain ____. A. completely filled energy sublevels B. 3 electrons in the energy level C. equal number of electrons and neutrons D. all of the above

29. 28. What is the maximum number of “d” orbitals in a principal energy level? A. 1 B. 3 C. 5 D. 7

30. 29. How are frequency and wavelength of light related. A
29. How are frequency and wavelength of light related? A. directly proportional B. inversely proportional C. the have no relation

31. 30. Which electron configuration would be more stable: A. 3d3 B. 3d5 C
30. Which electron configuration would be more stable: A. 3d3 B. 3d5 C. 3d7 D. 3d10

32. 31. Which variable is directly proportional to frequency: A. energy B
31. Which variable is directly proportional to frequency: A. energy B. wavelength C. the speed of light D. mass

33. 32. Which color of visible light has the shortest wavelength. A. red B
32. Which color of visible light has the shortest wavelength? A. red B. blue C. indigo D. violet

34. 33. How many electrons are in the highest occupied energy level of a neutral atom of arsenic? A. 2 B. 5 C. 10 D. 15

35. ANSWERS
1. B 11. B 21. C 31. A 2. C 12. C 22. A 32. D 3. B 13. A 23. B 33. B 4. B 14. D 24. D 5. D 15. B 25. C 6. C 16. C 26. B 7. C 17. B 27. A 8. B 18. B 28. C 9. B 19. A 29. B 10. A 20. D 30. D