Unit 4 – Electrons

Exam Review

1. What is the next atomic orbital in the series: 1s, 2s, 2p, 3s, 3p, ?

A. 3dB. 4sC. 4pD. 3f

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.

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

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. counterclockwiseC. it doesn’t spin because the cancel each

otherD. towards the nucleus

5. What is the approximate energy of a photon having a frequency of 4.0 x

1015 Hz? (h = 6.63 x 10-34 J . s)

A. 1.7 x 10-41 JB. 1.678 x 10-41 JC. 2.652 x 10-18 JD. 2.7 x 10-18 J

6. Which of the following would be most stable:

A. 4d5

B. 4d4

C. 4d10

D. 4f6

7. How many unpaired electrons are in a sulfur atom (Z = 16)?

A. 4B. 1C. 2D. 0

8. According to the Heisenberg uncertainty principle, if the position of a moving particle is known, what other quantity CANNOT be known?

A. energyB. velocity C. massD. none of the above

9. Which of the following has the highest frequency:

A. x-rays

B. gamma rays

C. radio waves D. UV rays

10. What is the electron configuration of potassium?

A. [Ar]4s1

B. [Ne]4s1

C. 1s12s12p63p6

D. 1s22p63s23p64s1

11. What is the number of electrons in the outermost energy level of an oxygen

atom?

A. 4B. 6C. 8D. 10

12. How does the speed of visible light compare with the speed of gamma rays, when both speeds are measured in a vacuum?

A. slowerB. fasterC. the sameD. you can’t compare them

13. The principal quantum number indicates what property of an electron?

A. the energy level of the electronB. the spin of the electronC. the sublevel of the electronD. the shape of the orbital

14. Which scientist developed the quantum mechanical model of the atom?

A. BohrB. HeisenbergC. de BroglieD. Schrödinger

15. What is the maximum number of electrons in the second principal energy level?

A. 2B. 8C. 18D. 32

16. If three electrons are available to fill three empty 2p atomic orbitals, how will the

electrons be distributed?

A. All in one orbitalB. 2 of them will be in one orbital; 1 in

anotherC. 1 electron in each orbitalD. they can’t all fit in the 2p orbitals

17. What is the wavelength of a wave that has a frequency of 60. MHz?

A. 5.0 x 106 mB. 5.0 mC. 5.0 x 103 mD. 5.0 x 10-1 m

18. When an electron moves from a lower to a higher energy level, the electron _____.

A. must give off a photon of energyB. must absorb a photon of energyC. must slow downD. must stay in the same position

19. According to the aufbau principle, electrons enter orbitals of ___ first.

A. lowest energyB. highest energyC. lowest monemtumD. highest momentum

20. What is the maximum number of “f” orbitals in any single energy level of

an atom?

A. 1B. 3 C. 5D. 7

21. What types of atomic orbitals (s, p, d, or f) are in the third principal energy level?

A. s and pB. s, p, and fC. s, p, and dD. s, p, d, and f

22. How would the atomic emission spectra of a sodium atom on Earth compare with sodium in the sun?

A. it would be the sameB. it would be differentC. you can’t compare the twoD. sodium doesn’t have an emission

spectra

23. How many energy sublevels are in the second principal energy level?

A. 1B. 2 C. 3D. 4

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 photonD. both b and c

25. Who predicted that all matter can behave as waves as well as particles?

A. Bohr B. SchrödingerC. de BroglieD. Plank

26. What are quanta of light called?

A. quantumsB. photonsC. electronsD. radiation

27. Stable electron configurations are likely to contain ____.

A. completely filled energy sublevelsB. 3 electrons in the energy levelC. equal number of electrons and

neutronsD. all of the above

28. What is the maximum number of “d” orbitals in a principal energy level?

A. 1B. 3C. 5D. 7

29. How are frequency and wavelength of light related?

A. directly proportionalB. inversely proportionalC. the have no relation

30. Which electron configuration would be more stable:

A. 3d3

B. 3d5

C. 3d7

D. 3d10

31. Which variable is directly proportional to frequency:

A. energyB. wavelength

C. the speed of light

D. mass

32. Which color of visible light has the shortest wavelength?

A. redB. blueC. indigoD. violet

33. How many electrons are in the highest occupied energy level of a neutral atom of arsenic?

A. 2 B. 5C. 10D. 15

ANSWERS1. B 11. B 21. C 31. A2. C 12. C 22. A 32. D3. B 13. A 23. B 33. B4. B 14. D 24. D5. D 15. B 25. C6. C 16. C 26. B7. C 17. B 27. A8. B 18. B 28. C9. B 19. A 29. B10. A 20. D 30. D