Republic of the Philippines Department of Education Regional Office IX, Zamboanga Peninsula 8 SCIENCE Quarter 3 - Module 8 PERIODIC PROPERTIES OF ELEMENTS Name of Learner: ___________________________ Grade & Section: ___________________________ Name of School: ___________________________ Science- Grade 8 Support Material for Independent Learning Engagement (SMILE) Quarter 3 - Module 8: Periodic Properties of Elements First Edition, 2021 Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for the exploitation of such work for a profit. Such agency or office may, among other things, impose as a condition the payment of royalty. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this book are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Development Team of the Module Writer: Galo M. Salinas Editor: Teodelen S. Aleta Reviewers: Teodelen S. Aleta, Zyhrine P. Mayormita Lay-out Artists: Zyhrine P. Mayormita, Chris Raymund M. Bermudo Management Team: Virgilio P. Batan Jr. - Schools Division Superintendent Lourma I. Poculan - Asst. Schools Division Superintendent Amelinda D. Montero - Chief Education Supervisor, CID Nur N. Hussien - Chief Education Supervisor, SGOD Ronillo S. Yarag - Education Program Supervisor, LRMS Zyhrine P. Mayormita - Education Program Supervisor, Science Leo Martinno O. Alejo - Project Development Officer II, LRMS Janette A. Zamoras - Public Schools District Supervisor Adrian G. Refugio - School Principal, Zamboanga del Norte NHS Printed in the Philippines by Department of Education – Region IX - Dipolog City Schools Division Office Address: Purok Farmers, Olingan, Dipolog City, Zamboanga del Norte, 7100 Telefax: (065) 212-6986 and (065) 212-5818 E-mail Address: [email protected] What I Need to Know The modern periodic table is a very valuable tool for predicting the chemistry of elements. It summarizes relationships that exist among elements and their compounds. Thus, many individual properties of elements need not be memorized if periodic relationships are known. This module will further broaden your knowledge about the elements. It allows you to explore the modern periodic table in terms of the following periodic properties of the elements: atomic size, ionization energy, metallic character, electronegativity, and electron affinity. After going through this module, you are expected to: 1. Use the periodic table to predict the chemical behavior of an element (S8MT- IIIi-j-12). Specifically, this module will let you recognize the trends in atomic size, ionization energy, metallic character, electronegativity, and electron affinity of elements across the period and down the family. What's In In the previous module, you were able to identify the elements in the modern periodic table arranged in groups and periods; representative and transition elements, metals, metalloids, and non-metals. In this module, we focus on the variations in atomic properties that are useful in predicting the chemical behavior of elements. Activity 1: The Periodic Properties Direction: Use the clues to solve the puzzle. Across 1. ability to attract electrons 4. repeating trends in element properties Down 2. ability to accept electrons 3. adj., the character of an atom to readily lose an electron 5. energy to remove an electron from an atom 1 What's New The periodic properties of elements can be related to human behavior. Below is a short excerpt from the chapter Argon in Primo Levi's book "The Periodic Table". “The little I know about my ancestors presents many similarities to these gases. Not all of them were materially inert, for that was not granted them. On the contrary, they were—or had to be— quite active, in order to earn a living and because of a reigning morality that held that “he who does not work shall not eat.” But there is no doubt that they were inert in their inner spirits, inclined to disinterested speculation, witty discourses, elegant, sophisticated, and gratuitous discussion. It can hardly be by chance that all deeds attributed to them, though quite various, have in common a touch of the static, an attitude of dignified abstention, of voluntary (or accepted) relegation to the margins of the great river of life.” Adopted from: What Element Are You Lesson Plan. https://kenanfellows.org//kfp-cp-sites/cp04/cp04/sites/kfp-cp- sites.localhost.com.cp04/files/What%20Element%20are%20You%20Lesson%20Plan.pdf According to Levi, a chemist, and writer, each element had an associative value—its properties symbolizing certain thoughts and activating specific memories. He describes Argon as a rare gas, part of the air we breathe and need to survive but not always noticed or appreciated. In what way does Levi identify with Argon? What does the element symbolize about his Jewish background? The rotations of planets, seasons, high and low tides are periodic processes in our solar system and nature. Ancient astronomers and astrologers used these observations to regulate the activities of individuals or even of nations. Periodicity is an essential part of our life, as evidenced by the beating of the heart and our eating, sleeping, and waking patterns. The elements in the periodic table are arranged in order of increasing atomic number. These elements display several other trends, and we can use the periodic table to predict their chemical, physical, and atomic properties. Activity 2: Connecting circles! Direction: Using graphs A and B, connect all circles by increasing atomic number with a thin straight line. Figure 1. Graphical Representation of Atomic Radius vs Atomic Number Source: http://homework.sdmesa.edu/dgergens/chem100l/periodicity/periodic_table_lab.pdf 2 Figure 2. Graphical Representation of First Ionization Energy vs Atomic Number Source: http://homework.sdmesa.edu/dgergens/chem100l/periodicity/periodic_table_lab.pdf Interpret the data as presented in the graph and answer these questions: 1. How do you describe the line that connects all circles in Graph A? What about Graph B? _________________________________________________________________ ____________________________________________________ 2. What does the line in Graph A mean? What about the line in Graph B? You may refer to the periodic table for your answer. ____________________________ ____________________________________________________ What is It The periodic law states that when the elements are arranged in order of increasing atomic number, their physical and chemical properties vary periodically. In this module, we will look at the following physical and chemical properties of an atom, namely; atomic size, ionization energy, metallic character, electronegativity, and electron affinity. Periodic trends are specific patterns present in the periodic table that illustrate different aspects of a certain element. The trends provide chemists with an invaluable tool to quickly predict an element's properties. These trends exist because of the similar atomic structure of the elements within their respective group families or periods and because of the periodic nature of the elements. Atomic Size The atomic radius of a chemical element is the measure of the size of its atoms. The atomic radius is one-half the distance between the nuclei of two atoms (just like a radius is half the diameter of a circle). Thus, based on the atomic radii, the atomic size patterns are observed throughout the periodic table. The following are the general trends in the size of atomic radii: Periodic table showing trends in atomic size Image Source: https://lavelle.chem.ucla.edu/forum/viewtopic. 3 1. Within each period (horizontal row), the atomic radius tends to decrease with the atomic number (nuclear charge). The largest atom in a period is a Group IA atom and the smallest is a Group VIIIA or noble gas atom. 2. Within each group (vertical column), the atomic radius tends to increase with the period number. Ionization Energy Ionization energy is the energy required to remove an electron from a neutral atom in its gaseous phase. Conceptually, ionization energy is the opposite of electronegativity. The lower this energy is, the more readily the atom becomes a cation. Therefore, the higher this energy is, the more unlikely it is that the atom becomes a cation (kat·ai·aan). Generally, Periodic table showing ionization energy trends Source: https://chem.libretexts.org/Bookshelves/Inorganic. elements on the right side of Chemistry/Modules_and_Websites_(Inorganic_Chemistry) /Descriptive_Chemistry/Periodic_Trends_of_Elemental_Properties/Periodic_Trends the periodic table have higher ionization energy because their outermost level occupied by the electron is nearly filled. Elements on the left side of the periodic table have low ionization energies because of their willingness to lose electrons and become cations. Thus, ionization energy increases from left to right on the periodic table. Metallic Character The metallic character of an element can be defined as how readily an atom can lose an electron. From right to left across a period, the metallic character increases because the attraction between the outermost electron and the atomic nucleus is weaker, enabling