Trends in the Periodic Table JOHAN N @johannwolfgangdobereiner Helloooooooo!! Just want to know the trends in the periodic table of elements #HelpMeGrade8 #TugsayMahusay DECODE ME! There will be a question to be posted and a set of numbers has provided as your guide. You are going to decode these numbers in order to reveal the answer. Each number corresponds a letter from the english alphabet. For 1=A, 2=B, 3=C, 4=D……26=Z and for 0=Space ATOMIC RADIUS It pertains to the size of an atom, the half of the distance between the nuclei of neighboring atoms. In this trend, the behavior of representative elements decreases in going from left to right across period. Within a family or group, it increases from top to bottom. 1, 20, 15, 13, 9, 3, 0, 18, 1, 4, 9, 21, 19 METALLIC PROPERTY It refers to the level of reactivity of a metal. In this trend, the behavior of representative elements decreases in going from left to right across period. Within a family or group, it increases from top to bottom. 13, 5, 20, 1, 12, 12, 9, 3, 0, 16, 18, 15, 16, 5, 18, 20, 25 ELECTRONEGATIVITY It measures the tendency of an atom to attract an electron. In this trend, the behavior of representative elements increases in going from left to right across period. Within a family or group, it increases from bottom to top. 5, 12, 5, 3, 20, 18, 15, 14, 5, 7, 1, 20, 9, 22, 9, 20, 25 IONIZATION ENERGY It is the minimum amount of energy required to remove an electron from a neutral atom in its gaseous phase. In this trend, the behavior of representative elements increases in going from left to right across period. Within a family or group, it increases from bottom to top. 9, 15, 14, 9, 26, 1, 20, 9, 15, 14, 0, 5, 14, 5, 18, 7, 25 1. ATOMIC RADIUS It pertains to the size of an atom, the half of the distance between the nuclei of neighboring atoms. ATOMIC RADIUS Which of the following elements have high atomic radius? 1. N vs F 2. N vs Al IONIC RADIUS Adding electrons makes an atom bigger, and taking one away makes it smaller. F Na F- + Na Which of the following have high ionic radius? 1. S vs S -2 2. Ca vs Ca 3. Br vs Kr +2 2. METALLIC PROPERTY It refers to the level of reactivity of a metal. Metallic property of an element depends on how readily it can lose its electrons. METALLIC PROPERTY Which of the following elements possess high metallic property 1. Ca vs. Rb 2. Na vs. Mg 3. ELECTRONEGATIVITY It refers to the tendency of an atom to attract an electron. F is the most electronegative atom Noble gases are not electronegative. ELECTRONEGATIVITY Which of the following elements have high electronegativity? 1. Cl vs. N 2. P vs. Si 4. IONIZATION ENERGY It is the minimum amount of energy required to remove an electron. IONIZATION ENERGY Which of the following elements have high ionization energy? 1. Al vs. S 2. N vs. Si Activity 1: Does the Atomic Size of the Elements vary with Atomic Number? Objectives: - - Find out the relationship between the atomic radius of selected elements and their atomic number. Describe the change in atomic radius of elements from Li to F and from Na to Cl. Materials: - Graphing paper - Pencil - Ruler Procedure: - Prepare a graph showing atomic radius plotted against atomic number. - Study the graph. Element Atomic Number H Li Be B C N O F Na Mg Al Si P S Cl (horizontal) 1 2 4 5 6 7 8 9 11 12 13 14 15 16 17 Atomic Radius (nm) (vertical) 0.037 0.133 0.089 0.080 0.077 0.074 0.074 0.072 0.157 0.136 0.125 0.117 0.110 0.104 0.099 K Ca Ga Ge As Se Br Rb Sr In Sn Sb Te I Cs 19 20 31 32 33 34 35 37 38 49 50 51 52 53 55 0.203 0.174 0.125 0.122 0.121 0.117 0.114 0.216 0.191 0.150 0.141 0.141 0.137 0.133 0.235 QUESTIONS: 1. What are the elements at the highest points? At the lowest points? 2. Do you see any cyclic pattern? 3. Describe the change in atomic radius of elements from Li to F and from Na to Cl. Is this repeated in other cycles? 4. Give the relationship between atomic number and atomic size of the elements within one cycle. Activity 2: Is Ionization Energy Dependent on Atomic Number? Objectives: - Look for the recurrence of high or low ionization energy values in the elements arranged in order of increasing atomic numbers. - Describe the variation of ionization energy with atomic number. Materials: - Graphing paper - Pencil - Ruler Procedure: 1. Copy the figure (Plot of Ionization energy vs. atomic number) 2. Study the position of each element in the plot and fill in the table with your data. Atomic number of elements at the highest points Elements at the highest points Interval in atomic number between elements at two successive highest points Elements at the lowest points Interval in atomic number between elements at two successive lowest points 1. 2. 3. 4. 5. Atomic number of the elements at the lowest points 1. 2. 3. 4. 5