Name Date Class MODELS OF THE ATOM

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1 Name Date Class 5.1 MODELS OF THE ATOM Section Review Objectives Identify inadequacies in the Rutherford atomic model Identify the new assumption in the Bohr model of the atom Describe the energies and positions of electrons according to the quantum mechanical model Describe how the shapes of orbitals at different sublevels vary Vocabulary energy levels quantum Part A Completion quantum mechanical model atomic orbital Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. The chemical properties of atoms, ions, and molecules 1. are related to the arrangement of the 1 within them. 2. Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved. The first modern atomic theory, proposed by 2, 3. portrayed the atom as a solid, indivisible mass. After the discovery 4. of the electron by 3, the atomic model was revised to 5. include them. J.J. Thomson s model is referred to as the 4 6. model. Rutherford pictured the atom as a dense 5 7. surrounded by electrons. In the Bohr model, the electrons move 8. in 6 paths. The 7 model is the modern description of the electrons in atoms. This model estimates the 8 of finding an electron within a certain volume of space surrounding the nucleus. Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 9. Electrons must have a certain minimum amount of energy called a quantum in order to move from one energy level to the next higher energy level. 10. The electron probability clouds for atomic orbitals are spherical in shape. Chapter 5 Electrons in Atoms 105

2 Name Class Date 11. The number of sublevels in an energy level is equal to the square of the principal quantum number of that energy level. 12. The maximum number of electrons that can occupy the fourth principal energy level of an atom is The higher the energy level occupied by an electron the more energetic it is. 14. The principal quantum number equals the number of sublevels within that principal energy level. Part C Matching Match each description in Column B to the correct term in Column A. Column A Column B 15. quantum 16. atomic orbitals 17. energy level 18. quantum mechanical model a. a region in space around the nucleus of an atom where an electron is likely to be moving b. the regions around the nucleus within which the electrons have the highest probability of being found c. the amount of energy required to move an electron from its present energy level to the next higher one d. the modern description of the behavior of electrons in atoms Part D Questions and Problems Answer the following in the space provided. 19. Summarize the development of atomic theory. 20. How many orbitals are in each of the following sublevels? a. 4p sublevel Prentice Hall, Inc. All rights reserved. b. 3d sublevel c. 4f sublevel d. 2s sublevel 106 Core Teaching Resources

3 Name Date Class 5.2 ELECTRON ARRANGEMENT IN ATOMS Section Review Objectives Describe how to write the electron configuration for an atom Explain why the actual electron configurations for some elements differ from those predicted by the Aufbau principle Vocabulary electron configurations Aufbau principle Pauli exclusion principle Hund s rule Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. The ways in which electrons are arranged around the nuclei 1. of atoms are called 1. The 2 describes the sequence 2. in which orbitals are filled. The various orbitals within a sublevel 3. Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved. of a principle energy level are always of 3 energy. The 4. 4 principle states that a maximum of only 5 5. electrons can occupy each orbital. To occupy the same orbital, two 6. electrons must have 6 spins. Hund s rule states that the 7. electrons pair up only after each orbital in a sublevel is occupied 8. by 7. When using the shorthand method for showing the 9. electron configuration of an atom, 8 are used to indicate 10. the number of 9 occupying each sublevel. Correct electron configurations can be obtained by using the Aufbau diagram for the elements up to and including vanadium. 10 and copper are exceptions to the Aufbau principle. Chapter 5 Electrons in Atoms 107

4 Name Class Date Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 11. The orbitals of a principal energy level are lower in energy than the orbitals in the next higher principal energy level. 12. The configuration 3d 4 4s 2 is more stable than the configuration 3d 5 4s As many as four electrons can occupy the same orbital. 14. The Pauli exclusion principle states that an atomic orbital may describe at most two electrons. 15. The electron configuration for potassium is 1s 2 2s 2 2p 6 3s 2 3p 6 4s The electron configuration for copper is 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 9. Part C Matching Match each description in Column B to the correct term in Column A. Column A Column B 17. electron configuration 18. Aufbau principle 19. Pauli exclusion principle 20. Hund s rule 21. neon a. When electrons occupy orbitals of equal energy, one electron enters each orbital until all the orbitals contain one electron with parallel spins. b. An atomic orbital may describe at most two electrons. c. 1s 2 2s 2 2p 6 d. Electrons enter orbitals of lowest energy first. e. the most stable arrangement of electrons around the nucleus of an atom Part D Questions and Problems Answer the following in the space provided. 22. Write the electron configurations for the following atoms. a. C c. K b. S d. Ar 23. Identify the elements described below: a. Contains a full third energy level. Prentice Hall, Inc. All rights reserved. b. Contains the first p electron. 108 Core Teaching Resources

5 Name Date Class 5.3 PHYSICS AND THE QUANTUM MECHANICAL MODEL Section Review Objectives Describe the relationship between the wavelength and frequency of light Explain how the frequencies of light are related to changes in electron energies Distinguish between quantum mechanics and classical mechanics Identify the cause of the atomic emission spectrum Vocabulary amplitude wavelength ( ) frequency ( ) hertz (Hz) electromagnetic radiation spectrum atomic emission spectrum ground state photons Heisenberg uncertainty principle Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved. Key Equations c E h h m Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. According to quantum mechanics, the motions of subatomic 1. particles may be described as 1. The frequency and 2. wavelength of all waves are 2 related. 3. Every element emits 3 if it is heated by passing an 4. electric discharge through its gas or vapor. Passing this emission 5. through a prism gives the 4 of the element The quantum concept developed from Planck s studies of 7. and Einstein's explanation of the 6 effect. Planck showed that the amount of radiant energy absorbed or emitted by a body is proportional to the 7 of the radiation. Chapter 5 Electrons in Atoms 109

6 Name Class Date Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 8. The speed of light is a constant that can be obtained by dividing the frequency of light by its wavelength. 9. The amplitude of a wave is the distance between the crests. 10. The energy of a body can change only in small discrete units. 11. The position and velocity of an electron in an atom can be determined with great certainty. 12. The photoelectric effect will occur no matter what frequency of light strikes a metal. Part C Matching Match each description in Column B to the correct term in Column A. Column A Column B 13. photons 14. de Broglie s equation 15. visible light 16. ground state 17. wavelength a. predicts that all matter exhibits wavelike motions b. the distance between two consecutive wave crests c. light quanta d. the lowest energy level for a given electron e. example of electromagnetic radiation Part D Questions and Problems Answer the following in the space provided. 18. What is the frequency of radiation whose wavelength is cm? 19. Apply quantum theory to explain the photoelectric effect. Prentice Hall, Inc. All rights reserved. 110 Core Teaching Resources