Review 6: Modern Atomic Theory. Copyright Cengage Learning. All rights reserved. 11 1

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1 Review 6: Modern Atomic Theory Copyright Cengage Learning. All rights reserved. 11 1

2 The concept of the nuclear atom left unanswered questions about 1. why the nucleus is so dense. 2. why the negative electrons do not collapse into the positive nucleus. 3. what isotopes are. 4. the mass of the nucleus. Copyright Cengage Learning. All rights reserved. 11 2

3 ANSWER Choice #2 properly explains that the nuclear atom did not explain the stable position of electrons relative to the positive nucleus. Copyright Cengage Learning. All rights reserved. 11 3

4 The relationship between the wavelength and frequency of radiation is expressed by the equation: 1. λν = c 2. λ = 1/ν 3. ν = cλ 4. ν = 1/c + λ Copyright Cengage Learning. All rights reserved. 11 4

5 ANSWER Choice #1 provides the correct relationship: Wavelength (λ) frequency (ν) = the speed of light in a vacuum (c) Copyright Cengage Learning. All rights reserved. 11 5

6 The concept of photons emphasizes the particle-like nature of light rather than its wave-like nature. A photon of infrared light has more energy in it than a photon of 1. visible light 2. ultraviolet light 3. x-rays 4. microwave radiation Copyright Cengage Learning. All rights reserved. 11 6

7 ANSWER Choice #4. X-rays, UV light, and visible radiation are all more energetic than infrared. Copyright Cengage Learning. All rights reserved. 11 7

8 When the electrons in atoms receive energy from a source, they go into an excited state but quickly return back to its ground state by 1. nuclear fusion. 2. emitting a photon of light. 3. emitting a proton. 4. absorbing heat. Copyright Cengage Learning. All rights reserved. 11 8

9 ANSWER Choice #2 correctly describes a common mode of relaxation of excited state atoms. Copyright Cengage Learning. All rights reserved. 11 9

10 The concept that electrons in an atom can only occupy specific energy levels is equivalent to saying that the energy levels are 1. varied. 2. quantized. 3. superimposed. 4. continuous. Copyright Cengage Learning. All rights reserved

11 ANSWER Choice #2 reflects the concept that there are specific allowable energy levels in which electrons can exist. Copyright Cengage Learning. All rights reserved

12 Which of the following is true regarding the atom? 1. All atoms of the same element are identical. 2. As verified by Rutherford, only positively charged particles called protons are found inside the nucleus. 3. Electrons located further from the nucleus have more predictable behavior because they contain less energy. 4. Electrons display both particle-like behavior (they have mass) and wave-like behavior (they are associated with probability). Copyright Cengage Learning. All rights reserved

13 ANSWER Choice #4 is the correct answer. Not all atoms of the same element are identical (due to isotopes and ions). Neutrons are also found in the nucleus of an atom in addition to protons. Electrons located further from the nucleus have less predictable behavior and contain more energy. Copyright Cengage Learning. All rights reserved

14 When an electron is excited in an atom or ion 1. only specific quantities of energy are released in order for the electron to return to its ground state. 2. white light is never observed when the electron returns to its ground state. 3. the electron is only excited to certain energy levels. 4. All of the above statements are true when an electron is excited. Copyright Cengage Learning. All rights reserved

15 ANSWER Choice #4 is the correct answer. Copyright Cengage Learning. All rights reserved

16 How many of the following statements are true concerning an electron in its ground state? I. The electron must be in its lowest-energy state. II. Energy must be applied to the electron in order to excite it. III. The electron must be located on the nucleus of an atom. IV. The electron can release energy to obtain a lower ground state Copyright Cengage Learning. All rights reserved

17 ANSWER Choice #2 is the correct answer. I and II are correct. Copyright Cengage Learning. All rights reserved

18 The Bohr model of the hydrogen atom explained the emission spectrum of the hydrogen atom with the concept of 1. quantized energy levels. 2. quantized electron orbits. 3. transitions of electrons from higher to lower energy levels. 4. all of the above Copyright Cengage Learning. All rights reserved

19 ANSWER Choice #4 reflects the quantized nature of the electron energy levels and the production of photons of specific energies that correspond to transitions between quantized levels. Copyright Cengage Learning. All rights reserved

20 The atomic model developed by Neils Bohr only works for the hydrogen atom. Choose the best answer that describes why this model does not work for other atoms. 1. The hydrogen atom has only one proton. The nuclei of other atoms would be able to pull the electrons out of their orbits. 2. The hydrogen atom has only one electron. Since other elements have more than one electron, the repulsions between electrons cannot be described by this model. 3. Other atoms are larger than hydrogen atoms, so they fill up too much space to be defined by orbits. 4. Hydrogen is the only element that has quantized energy levels like those described by this model. Copyright Cengage Learning. All rights reserved

21 ANSWER Choice #2 is the correct answer. Copyright Cengage Learning. All rights reserved

22 In the wave mechanical model of the atom, electron orbitals are probability density diagrams of where the electron is likely to be found. These maps of where the electron is most likely to be were developed 1. from atomic emission spectra. 2. by Niels Bohr. 3. by experiments with a cathode ray tube. 4. from mathematical analyses by Schrödinger. Copyright Cengage Learning. All rights reserved

23 ANSWER Choice #4 presents the idea that electron orbitals are mathematical descriptions of electron probability densities, derived from solutions to the Schrödinger equation. Copyright Cengage Learning. All rights reserved

24 At the third principal energy level of an atom, the number of orbitals equals Copyright Cengage Learning. All rights reserved

25 ANSWER Choice #3 correctly identifies the sum of the orbitals at that level: one 3s orbital + three 3p orbitals + five 3d orbitals = nine orbitals. Copyright Cengage Learning. All rights reserved

26 The number of electrons that can be accommodated in the n = 2 level is: Copyright Cengage Learning. All rights reserved

27 ANSWER Choice #4 correctly predicts that 8 electrons can fit in the n = 2 level. Two electrons fill the 2s orbital and 6 electrons fill the set of three 2p orbitals. Copyright Cengage Learning. All rights reserved

28 Which of the following statements best describes the movement of electrons in a p orbital? 1. The electron movement cannot be exactly determined. 2. The electrons move within the two lobes of the p orbital, but never beyond the outside surface of the orbital. 3. The electrons are concentrated at the center (node) of the two lobes. 4. The electrons move along the outer surface of the p orbital, similar to a figure 8 type of movement. Copyright Cengage Learning. All rights reserved

29 ANSWER Choice #1 is the correct answer. Copyright Cengage Learning. All rights reserved

30 Write out the electron configuration for an atom of phosphorus and indicate the number of unpaired electrons 1. [Ne]3s 2 3p 3 ; 3 unpaired electrons 2. [Ne]2s 2 2p 6 3s 2 3p 3 ; 3 unpaired electrons 3. [Ne]3s 2 3p 3 ; 5 unpaired electrons 4. [Ne]3p 5 ; 5 unpaired electrons Copyright Cengage Learning. All rights reserved

31 ANSWER Choice #1 is correct. Each of the three 3p orbitals has one unpaired electron in it. The electrons in the 3s orbital are paired. Copyright Cengage Learning. All rights reserved

32 The number of valence electrons in an atom of Cl is : Copyright Cengage Learning. All rights reserved

33 ANSWER Choice #1 is correct. Cl has 2 valence electrons in the 3s orbital and 5 in the 3p subset. Copyright Cengage Learning. All rights reserved

34 How many unpaired electrons does sulfur contain in its ground state? Copyright Cengage Learning. All rights reserved

35 ANSWER Choice #3 is correct. There are 4 electrons in the p orbitals, with one of the p orbitals containing paired electrons and two of the p orbitals containing unpaired electrons. Copyright Cengage Learning. All rights reserved

36 How many unpaired electrons does the element cobalt (Co) have in its lowest energy state? Copyright Cengage Learning. All rights reserved

37 ANSWER Choice #3 is correct. There are 7 electrons in the d orbitals, with two of the d orbitals containing paired electrons and three of the d orbitals containing unpaired electrons. Copyright Cengage Learning. All rights reserved

38 Can an electron in a phosphorus atom ever be in a 3d orbital? Choose the best answer. 1. Yes. An electron can be excited into a 3d orbital. 2. Yes. A ground-state electron in phosphorus is located in a 3d orbital. 3. No. Only transition metal atoms can have electrons located in the d orbitals. 4. No. This would not correspond to phosphorus electron arrangement in its ground state. Copyright Cengage Learning. All rights reserved

39 ANSWER Choice #1 is the correct answer. Copyright Cengage Learning. All rights reserved

40 The Lanthanides correspond to filling up the set of orbitals. 1. 3d 2. 3f 3. 4f 4. 5f Copyright Cengage Learning. All rights reserved

41 ANSWER Choice #3 correctly associates the 14 elements that make up the lanthanides with 14 available slots for electrons in the set of seven 4f orbitals. Copyright Cengage Learning. All rights reserved

42 Determine the expected electron configuration for the element Eu. 1. [Xe]6s 2 4f 6 2. [Rn]7s 2 5f 7 3. [Xe]4f 7 4. [Xe]6s 2 4f 7 Copyright Cengage Learning. All rights reserved

43 ANSWER Choice #4 is the correct answer. Copyright Cengage Learning. All rights reserved

44 Which element would be likely to have the lowest ionization energy? 1. Na 2. Al 3. Cl 4. Cs Copyright Cengage Learning. All rights reserved

45 ANSWER Choice #4 should be selected. Ionization energy increases from left to right, but decreases from top to bottom. Copyright Cengage Learning. All rights reserved

46 Which of the following elements has the largest ionization energy? 1. P 2. Al 3. Cl 4. K Copyright Cengage Learning. All rights reserved

47 ANSWER Choice #3 is the correct answer. Ionization energy increases from left to right, but decreases from top to bottom. Copyright Cengage Learning. All rights reserved

48 Which of the following elements has the largest ionization energy? 1. S 2. Ba 3. Cr 4. Mg Copyright Cengage Learning. All rights reserved

49 ANSWER Choice #1 is the correct answer. Ionization energy increases from left to right, but decreases from top to bottom. Copyright Cengage Learning. All rights reserved

50 Which of the following atoms is likely to have the largest atomic radius? 1. Na 2. Al 3. Cl 4. K Copyright Cengage Learning. All rights reserved

51 ANSWER Choice #4. Atomic radius decreases as one proceeds across the third period, but increases from top to bottom. Copyright Cengage Learning. All rights reserved

52 Which of the following atoms is likely to have the largest atomic radius? 1. Ca 2. Sr 3. N 4. Al Copyright Cengage Learning. All rights reserved

53 ANSWER Choice #2. Atomic radius decreases as one proceeds across the third period, but increases from top to bottom. Copyright Cengage Learning. All rights reserved

54 Which of the following is ranked in order of largest to smallest atomic radius? 1. F > S > Ge > Mn > Rb 2. Mn > Rb > F > S > Ge 3. Rb > Mn > Ge > S > F 4. Rb > Ge > Mn > F > S Copyright Cengage Learning. All rights reserved

55 ANSWER Choice #3. Atomic radius decreases as one proceeds across the third period, but increases from top to bottom. Copyright Cengage Learning. All rights reserved

56 Rank the following from smallest to largest atomic radius. 1. O, Zn, Ca, Ba 2. O, Ca, Zn, Ba 3. Ba, Ca, Zn, O 4. O, Zn, Ba, Ca Copyright Cengage Learning. All rights reserved

57 ANSWER Choice #1. Atomic radius decreases as one proceeds across the third period, but increases from top to bottom. Copyright Cengage Learning. All rights reserved

58 Which has a smaller atomic radius, an atom of fluorine or an atom of lithium? Choose the best answer. 1. They are the same size because their electrons are contained in the same principle energy level. 2. An atom of lithium is smaller than an atom of fluorine because lithium has fewer protons. 3. An atom of fluorine is smaller than an atom of lithium because with more protons the electrons are pulled closer to the nucleus. 4. An atom of fluorine is smaller than an atom of lithium because fluorine has a high ionization energy and will not lose electrons as easily as lithium. Copyright Cengage Learning. All rights reserved

59 ANSWER Choice #3 is the correct answer. Copyright Cengage Learning. All rights reserved

60 Which of the following statements is true? 1. The krypton 1s orbital is larger than the helium 1s orbital because krypton contains more electrons. 2. The krypton 1s orbital is smaller than the helium 1s orbital because krypton s nuclear charge draws the electrons closer. 3. The krypton 1s orbital and helium 1s orbital are the same size because both s orbitals can only have two electrons. 4. The krypton 1s orbital is larger than the helium 1s orbital because krypton s ionization energy is lower so it s easier to remove electrons. Copyright Cengage Learning. All rights reserved

61 ANSWER Choice #2 is the correct answer. Copyright Cengage Learning. All rights reserved

62 Congratulations you have finished review #6 Please stop by during academy if you need help with any of the questions presented in this review. Please click on the following link and send me an telling me that you completed this review. Be sure to indicate Review # 6 in your . Thank you. Mrs. Baldessari's Copyright Cengage Learning. All rights reserved