Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mendeleev and Chemical Periodicity Mendeleev noticed that when the elements were arranged in order of increasing atomic mass, certain similarities in their chemical properties appeared at regular intervals. Repeating patterns are referred to as periodic. Mendeleev created a table in which elements with similar properties were grouped together—a periodic table of the elements. Chapter 5 Section 1 History of the Periodic Table

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mendeleev and Chemical Periodicity, continued After Mendeleev placed all the known elements in his periodic table, several empty spaces were left. In 1871 Mendeleev predicted the existence and properties of elements that would fill three of the spaces. By 1886, all three of these elements had been discovered. Chapter 5 Section 1 History of the Periodic Table

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Properties of Some Elements Predicted By Mendeleev Chapter 5 Section 1 History of the Periodic Table

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Moseley and the Periodic Law In 1911, the English scientist Henry Moseley discovered that the elements fit into patterns better when they were arranged according to atomic number, rather than atomic weight. The Periodic Law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers. Chapter 5 Section 1 History of the Periodic Table

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Modern Periodic Table The Periodic Table is an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group. Chapter 5 Section 1 History of the Periodic Table

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Electron Configurations and the Periodic Table

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Periods and Blocks of the Periodic Table Elements are arranged vertically in the periodic table in groups that share similar chemical properties. Elements are also organized horizontally in rows, or periods. The length of each period is determined by the number of electrons that can occupy the sublevels being filled in that period. Section 2 Electron Configuration and the Periodic Table Chapter 5 The periodic table is divided into four blocks, the s, p, d, and f blocks. The name of each block is determined by the electron sublevel being filled in that block.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Group 1  Alkali Metals  Ends in s 1  Soft, silvery metals  Highly reactive  Low density & melting point

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Group 2  Alkaline Earth Metals  Valence shell is s 2  Denser, harder, stronger than Alkali Metals  Less reactive than alkali metals

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Groups 3 – 12  Transition metals  Elements are a little less predictable

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Metalloids  Along the staircase starting in Group 13  Valence levels  p orbital  Share properties of metals & nonmetals  Referred to as semimetals  Used as semiconductors in electronics

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Group 17  Halogens  Valence level is s 2 p 5  Highly reactive NONmetals  Forms salts when combined with Group 1 or 2 metals

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Group 18  Noble Gases  Valence level is s 2 p 6  Usually unreactive

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Lanthanides (f-block)  Top Row of f-block  Shiny metals similar to Group 2  Actinides  Bottom Row of f-block  Naturally radioactive elements

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Electron Configuration and the Periodic Table Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem A  a. Without looking at the periodic table, identify the group, period, and block in which the element that has the electron configuration [Xe]6 s 2 is located.  b. Without looking at the periodic table, write the electron configuration for the Group 1 element in the third period. Is this element likely to be more reactive or less reactive than the element described in (a)? Periods and Blocks of the Periodic Table, continued Section 2 Electron Configuration and the Periodic Table Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem B  An element has the electron configuration [Kr]4 d 5 5 s 1. Without looking at the periodic table, identify the period, block, and group in which this element is located. Section 2 Electron Configuration and the Periodic Table Chapter 5 Periods and Blocks of the Periodic Table, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem C  Without looking at the periodic table, write the outer electron configuration for the Group 14 element in the second period. Then, name the element, and identify it as a metal, nonmetal, or metalloid. Section 2 Electron Configuration and the Periodic Table Chapter 5 Periods and Blocks of the Periodic Table, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem D  Name the block and group in which each of the following elements is located in the periodic table. Then, use the periodic table to name each element. Identify each element as a metal, nonmetal, or metalloid. Finally, describe whether each element has high reactivity or low reactivity.  a. [Xe]4 f 14 5 d 9 6 s 1 c. [Ne]3 s 2 3 p 6  b. [Ne]3 s 2 3 p 5 d. [Xe]4 f 6 6 s 2 Section 2 Electron Configuration and the Periodic Table Chapter 5 Periods and Blocks of the Periodic Table, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lesson Starter Define trend. Describe some trends you can observe, such as in fashion, behavior, color, design, and foods. How are trends used to classify? Section 3 Electron Configuration and Periodic Properties Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Periodic Trends

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Down a group Increases Adding on extra electron orbitals Stacking orbitals keep getting bigger Across a period Decreases More protons become ATTRACTED to more electrons

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem E  Of the elements magnesium, Mg, chlorine, Cl, sodium, Na, and phosphorus, P, which has the largest atomic radius? Explain your answer in terms of trends of the periodic table. Section 3 Electron Configuration and Periodic Properties Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Atom’s ability to steal an e -  Decreases down a group  Increases across a period Increases Decreases

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionization Energy, continued Section 3 Trends in the Periodic Table Chapter 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Periodic trends in ionization energy are shown in the graph below. Section 3 Electron Configuration and Periodic Properties Chapter 5 Ionization Energy, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem F  Consider two main-group elements, A and B. Element A has a first ionization energy of 419 kJ/mol. Element B has a first ionization energy of 1000 kJ/mol. Decide if each element is more likely to be in the s block or p block. Which element is more likely to form a positive ion? Section 3 Electron Configuration and Periodic Properties Chapter 5 Ionization Energy, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem F Solution Element A has a very low ionization energy, which means that atoms of A lose electrons easily. Element A is most likely to be an s -block metal because ionization energies increase across the periods. Element B has a very high ionization energy which means that atoms of B have difficulty losing electrons. Element B would most likely lie at the end of a period in the p block. Element A is more likely to form a positive ion because it has a much lower ionization energy than element B does. Section 3 Electron Configuration and Periodic Properties Chapter 5 Ionization Energy, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Atom’s ability to attract an e -  Decreases down a group  Increases across a period Increases Decreases

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Sample Problem G  Of the elements gallium, Ga, bromine, Br, and calcium, Ca, which has the highest electronegativity? Explain your answer in terms of periodic trends. Section 3 Electron Configuration and Periodic Properties Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu  Atom’s ability to accept an e -  Decreases down a group  Increases across a period Increases Decreases

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 1. In the modern periodic table, elements are arranged according to A. decreasing atomic mass. B. Mendeleev’s original model. C. increasing atomic number. D. when they were discovered. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 1. In the modern periodic table, elements are arranged according to A. decreasing atomic mass. B. Mendeleev’s original model. C. increasing atomic number. D. when they were discovered. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 2. Group 17 elements, the halogens, are the most reactive of the nonmetal elements because they A. require only one electron to fill their outer energy level. B. have the highest ionization energies. C. have the largest atomic radii. D. are the farthest to the right in the periodic table. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 2. Group 17 elements, the halogens, are the most reactive of the nonmetal elements because they A. require only one electron to fill their outer energy level. B. have the highest ionization energies. C. have the largest atomic radii. D. are the farthest to the right in the periodic table. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 3. The periodic law states that A. the chemical properties of elements can be grouped according to periodicity. B. the properties of the elements are functions of atomic mass. C. all elements in the same group have the same number of valence electrons. D. all elements with the same number of occupied energy levels must be in the same group. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 3. The periodic law states that A. the chemical properties of elements can be grouped according to periodicity. B. the properties of the elements are functions of atomic mass. C. all elements in the same group have the same number of valence electrons. D. all elements with the same number of occupied energy levels must be in the same group. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 4. As you move left to right across Period 3 from Mg to Cl, the energy needed to remove an electron from an atom A. generally increases. B. generally decreases. C. does not change. D. varies unpredictably. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 4. As you move left to right across Period 3 from Mg to Cl, the energy needed to remove an electron from an atom A. generally increases. B. generally decreases. C. does not change. D. varies unpredictably. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 5. Which of the following elements has the highest electronegativity? A. oxygen. B. hydrogen. C. fluorine. D. carbon. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 5. Which of the following elements has the highest electronegativity? A. oxygen. B. hydrogen. C. fluorine. D. carbon. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 6. The noble gases have A. high ionization energies. B. high electron affinities. C. large atomic radii. D. a tendency to form both cations and anions. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 6. The noble gases have A. high ionization energies. B. high electron affinities. C. large atomic radii. D. a tendency to form both cations and anions. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 7. Which electron configuration is not correct? A. O 2– [He]2 s 2 2 p 6 B. Mg 2+ [He]2 s 2 2 p 6 C. V 3+ [Ar]3 d 2 D. Al 3+ [Ar]2 s 2 2 p 6 Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 7. Which electron configuration is not correct? A. O 2– [He]2 s 2 2 p 6 B. Mg 2+ [He]2 s 2 2 p 6 C. V 3+ [Ar]3 d 2 D. Al 3+ [Ar]2 s 2 2 p 6 Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 8. Which two elements are more likely to have the same charge on their ions? A. Se and As B. Sn and Si C. Ca and Rb D. I and Xe Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 8. Which two elements are more likely to have the same charge on their ions? A. Se and As B. Sn and Si C. Ca and Rb D. I and Xe Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 9. Which list ranks the elements Sr, Te, Kr, Ru, and Cs in order of increasing electron affinity? A. Sr < Te < Ru < Cs < Kr B. Te < Ru < Sr < Cs < Kr C. Cs < Sr < Ru < Te < Kr D. Kr < Cs < Sr < Ru < Te Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 9. Which list ranks the elements Sr, Te, Kr, Ru, and Cs in order of increasing electron affinity? A. Sr < Te < Ru < Cs < Kr B. Te < Ru < Sr < Cs < Kr C. Cs < Sr < Ru < Te < Kr D. Kr < Cs < Sr < Ru < Te Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 11. What group most commonly forms 2– ions? Explain your reasoning. Standardized Test Preparation Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 11. What group most commonly forms 2– ions? Explain your reasoning. Answer: Group 16 most commonly forms 2– ions, because these elements require only two more electrons to fill their shell (obtain a noble-gas configuration). Standardized Test Preparation Chapter 5