Chapter 6 The Periodic Table PDF

Chapter 6 The Periodic Table Copyright © McGraw-Hill Education Section 1: Development of the Modern Periodic Table How was the periodic table developed? What are the key features of the periodic table? Copyright © McGraw-Hill Education D...

Chapter 6 The Periodic Table Copyright © McGraw-Hill Education Section 1: Development of the Modern Periodic Table How was the periodic table developed? What are the key features of the periodic table? Copyright © McGraw-Hill Education Development of the Modern Periodic Table Vocabulary Review New continued atomic number alkaline earth metal transition metal New inner transition metal periodic law lanthanide series group actinide series period nonmetal representative element transition element halogen metal noble gas alkali metal metalloid Copyright © McGraw-Hill Education Development of the Modern Periodic Table Development of the Periodic Table In the 1700s, Lavoisier compiled a list of all the known elements of the time. Copyright © McGraw-Hill Education Development of the Modern Periodic Table Development of the Periodic Table The 1800s brought large amounts of information and scientists needed a way to organize knowledge about elements. John Newlands proposed an arrangement where elements were ordered by increasing atomic mass. Copyright © McGraw-Hill Education Development of the Modern Periodic Table Development of the Periodic Table Newlands noticed when the elements were arranged by increasing atomic mass, their properties repeated every eighth element. Development of the Modern Periodic Table Development of the Periodic Table Meyer and Mendeleev both demonstrated a connection between atomic mass and elemental properties. Moseley rearranged the table by increasing atomic number, and resulted in a clear periodic pattern. Periodic repetition of chemical and physical properties of the elements when they are arranged by increasing atomic number is called periodic law. Copyright © McGraw-Hill Education Development of the Modern Periodic Table Copyright © McGraw-Hill Education Development of the Modern Periodic Table The Modern Periodic Table The modern periodic table contains boxes that contain the element's name, symbol, atomic number, and atomic mass. Copyright © McGraw-Hill Education Development of the Modern Periodic Table The Modern Periodic Table Columns of elements are called groups. Rows of elements are called periods. Elements in groups 1,2, and 13–18 possess a wide variety of chemical and physical properties and are called the representative elements. Elements in groups 3–12 are known as the transition metals. Copyright © McGraw-Hill Education Development of the Modern Periodic Table The Modern Periodic Table Elements are classified as metals, nonmetals, and metalloids. Metals are elements that are generally shiny when smooth and clean, solid at room temperature, and good conductors of heat and electricity. Alkali metals are all the elements in group 1 except hydrogen, and are very reactive. Alkaline earth metals are in group 2, and are also highly reactive. Copyright © McGraw-Hill Education Development of the Modern Periodic Table The Modern Periodic Table The transition elements are divided into transition metals and inner transition metals. The two sets of inner transition metals are called the lanthanide series and actinide series and are located at the bottom of the periodic table. Copyright © McGraw-Hill Education Development of the Modern Periodic Table The Modern Periodic Table Nonmetals are elements that are generally gases or brittle, dull-looking solids, and poor conductors of heat and electricity. Group 17 is composed of highly reactive elements called halogens. Group 18 gases are extremely unreactive and commonly called noble gases. Metalloids, such as silicon and germanium, have physical and chemical properties of both metals and nonmetals. Copyright © McGraw-Hill Education Development of the Modern Periodic Table The Modern Periodic Table Copyright © McGraw-Hill Education Development of the Modern Periodic Table Review Essential Questions How was the periodic table developed? What are the key features of the periodic table? Vocabulary periodic law metal lanthanide series group alkali metal actinide series period alkaline earth metal nonmetal representative transition metal halogen element inner transition metal noble gas transition element metalloid Copyright © McGraw-Hill Education Development of the Modern Periodic Table Section 2: Classification of Elements Why do elements in the same group have similar properties? Based on their electron configurations, what are the four blocks of the periodic table? Copyright © McGraw-Hill Education Classification of the Elements Organizing the Elements by Electron Configuration Recall electrons in the highest principal energy level are called valence electrons. All group 1 elements have one valence electron. Copyright © McGraw-Hill Education Classification of the Elements Organizing the Elements by Electron Configuration Group 2 elements have two valence electrons. The number of valence electrons for elements in groups 13–18 is ten less than their group number. The energy level of an element’s valence electrons indicates the period on the periodic table in which it is found. Copyright © McGraw-Hill Education Classification of the Elements The s-, p-, d-, and f-Block Elements The shape of the periodic table becomes clear if it is divided into blocks representing the atom’s energy sublevel being filled with valence electrons. Copyright © McGraw-Hill Education Classification of the Elements The s-, p-, d-, and f-Block Elements s-block elements consist of group 1 and 2, and the element helium. Group 1 elements have a partially filled s orbital with one electron. Group 2 elements have a completely filled s orbital with two electrons. Copyright © McGraw-Hill Education Classification of the Elements The s-, p-, d-, and f-Block Elements Groups 13–18 fill the p orbitals. In group 18, both the s and p orbitals of the period’s principal energy level are completely filled. Copyright © McGraw-Hill Education Classification of the Elements The s-, p-, d-, and f-Block Elements The d-block contains the transition metals and is the largest block. There are exceptions, but d-block elements usually have filled outermost s orbitals, and filled or partially filled d orbitals. The five d orbitals can hold 10 electrons, so the d-block spans ten groups on the periodic table. Copyright © McGraw-Hill Education Classification of the Elements The s-, p-, d-, and f-Block Elements The f-block contains the inner transition metals. f-block elements have filled or partially filled outermost s orbitals and filled or partially filled 4f and 5f orbitals. The 7f orbitals hold 14 electrons, and the inner transition metals span 14 groups. Copyright © McGraw-Hill Education Classification of the Elements Electron Configuration and the Periodic Table SOLVE FOR THE UNKNOWN Use with Example Problem 1. For representative elements, the Problem number of valence electrons can Strontium, which is used to produce red indicate the group number. fireworks, has an electron configuration of The s2 indicates the strontium’s valence [Kr]5s2. Without using the periodic table, electrons fill the s sublevel. Thus, determine the group, period, and block of strontium is in group 2 of the s-block. strontium. The number of the highest energy Response level indicates the period number. ANALYZE THE PROBLEM The 5 is 5s2 indicates that strontium is in You are given the electron configuration period 5. of strontium. EVALUATE THE ANSWER KNOWN UNKNOWN The relationships between electron Electron configuration = [Kr]5s2 Group = ? configuration and position on the periodic Period = ? table have been correctly applied. Block = ? Copyright © McGraw-Hill Education Classification of the Elements Review Essential Questions Why do elements in the same group have similar properties? Based on their electron configurations, what are the four blocks of the periodic table? Copyright © McGraw-Hill Education Classification of the Elements Section 3: Periodic Trends What are the period and group trends of different properties? How are period and group trends in atomic radii related to electron configuration? Copyright © McGraw-Hill Education Periodic Trends Vocabulary Review New principal energy level ion ionization energy octet rule electronegativity Copyright © McGraw-Hill Education Periodic Trends Forces that influence in atomic radius- Ionic radius –Ionization energy – Electronegativity Electrostatic repulsion –force of repulsion between particles or objects with like electric charges. Electrostatic force-Force of attraction between protons and electrons in an atom. ( this force depends on distance) Strong Nuclear force- holds atomic nucleus together. Binds protons and neutrons(nucleons) together. To overcome repulsive electromagnetic force. – Provides nuclear stability – Binding force of the nucleus – Important for nuclear reactions Atomic Radius Atomic size is a periodic trend influenced by electron configuration. For metals, atomic radius is half the distance between adjacent nuclei in a crystal of the element. Copyright © McGraw-Hill Education Periodic Trends Atomic Radius For elements that occur as molecules, the atomic radius is half the distance between nuclei of identical atoms that are chemically bonded together. Copyright © McGraw-Hill Education Periodic Trends Atomic Radius Atomic radius generally decreases from left to right, caused by increasing positive charge in the nucleus. ( electrostatic force) Valence electrons are not shielded from the increasing nuclear charge because no additional electrons come between the nucleus and the valence electrons.(period=same principal quantum orbital) Atomic radius generally increases as you move down a group. The outermost orbital size increases down a group, making the atom larger. (there is a change in period= principal quantum orbital). The addition of a larger principal orbital means that the outer electrons are farther apart from the nucleus. This distance offsets the pull (electrostatic force) of the increase nuclear charge. Additional orbitals between the outer electrons and the nucleus are occupied. These electrons shield the outer electrons from the nucleus( electrostatic repulsion) Copyright © McGraw-Hill Education Periodic Trends Atomic Radius Copyright © McGraw-Hill Education Periodic Trends Interpret Trends in Atomic Radii Use with Example Problem 2. SOLVE FOR THE UNKNOWN Problem Which has the largest atomic radius: Determine the periods. carbon (C), fluorine (F), beryllium (Be), or From the periodic table, all the elements are lithium (Li)? Answer without referring to found to be in period 2. Figure 11 (slide 7). Explain your answer in Apply the trend of decreasing radii terms of trends in atomic radii. across a period. Ordering the elements from left-to-right Response across the period yields: Li, Be, C, and F. ANALYZE THE PROBLEM The first element in period 2, lithium, has the You are given four elements. First, largest radius. determine the groups and periods the elements occupy. Then apply the general EVALUATE THE ANSWER trends in atomic radii to determine which has the largest atomic radius. The period trend in atomic radii has been correctly applied. Checking radii values in Figure 11 (slide 7) verifies the answer. Copyright © McGraw-Hill Education Periodic Trends Ionic Radius An ion is an atom or bonded group of atoms with a positive or negative charge. When atoms lose electrons and form positively charged ions, they always become smaller for two reasons: 1. The loss of a valence electron can leave an empty outer orbital, resulting in a smaller radius. 2. Electrostatic repulsion decreases allowing the electrons to be pulled closer to the nucleus. Copyright © McGraw-Hill Education Periodic Trends Electrostatic repulsion and Ionic radius Electrostatic repulsion- Force of repulsion between particles or objects with like electric charges. Removing an electron decreases the electrostatic repulsion. Adding an electron increases the electrostatic repulsion Ionic Radius When atoms gain electrons, they can become larger, because the addition of an electron increases electrostatic repulsion. Copyright © McGraw-Hill Education Periodic Trends Ionic Radius The ionic radii of positive ions generally decrease from left to right. The ionic radii of negative ions generally decrease from left to right, beginning with group 15 or 16. Both positive and negative ions increase in size moving down a group. Copyright © McGraw-Hill Education Periodic Trends Ionic Radius Copyright © McGraw-Hill Education Periodic Trends Ionization Energy Ionization energy is defined as the energy required to remove an electron from a gaseous atom. The energy required to remove the first electron is called the first ionization energy. Copyright © McGraw-Hill Education Periodic Trends Ionization Energy Copyright © McGraw-Hill Education Periodic Trends Ionization Energy Removing the second electron requires more energy, and is called the second ionization energy. Each successive ionization requires more energy, but it is not a steady increase. Copyright © McGraw-Hill Education Periodic Trends Ionization Energy First ionization energy increases from left to right across a period. First ionization energy decreases down a group because atomic size increases and less energy is required to remove an electron farther from the nucleus. Copyright © McGraw-Hill Education Periodic Trends Ionization Energy The ionization at which the large increase in energy occurs is related to the number of valence electrons. The octet rule states that atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons. The octet rule is useful for predicting what types of ions an element is likely to form. Copyright © McGraw-Hill Education Periodic Trends Electronegativity The electronegativity of an element indicates its relative ability to attract electrons in a chemical bond. Electronegativity decreases down a group and increases left to right across a period. Copyright © McGraw-Hill Education Periodic Trends Review Essential Questions What are the period and group trends of different properties? How are period and group trends in atomic radii related to electron configuration? Vocabulary ion ionization energy octet rule electronegativity Copyright © McGraw-Hill Education Periodic Trends  In which pair is the one on the left larger than the one on the right? a. Na, Rb b. S, Mg c. Br, Br- d. K, K+ Copyright © McGraw-Hill Education Periodic Trends