Exam (elaborations) GIZMOS Periodic Trends Gizmo Answers

Exam (elaborations) GIZMOS Periodic Trends Gizmo Answers Vocabulary: atomic radius, electron affinity, electron cloud, energy level, group, ion, ionization energy, metal, nonmetal, nucleus, period, periodic trends, picometer, valence electron Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. On the image at right, the two magnets are the same. Which paper clip would be harder to remove? 2. Which magnet would be most likely to attract additional paper clips? 3. What is the relationship between the thickness of the book and the ability of the magnet to hold on to and attract paper clips? Gizmo Warm-up Just as the thickness of a book changes how strongly a magnet attracts a paper clip, the size of an atom determines how strongly the nucleus attracts electrons. In the Periodic Trends Gizmo, you will explore this relationship and how it affects the properties of different elements. The atomic radius is a measure of the size of the electron cloud, or the region where electrons can be found. To begin, check that H (hydrogen) is selected in Group 1 on the left. Turn on Show ruler. To measure the radius, drag one end of the ruler to the proton in the nucleus and the other end to the electron. Click Save radius to record the value. Name: Date: B B The thicker the book the less atraction the magnet will have with the paper clip. The book thickness blocks that strength of the magnet's ability to attract things. 1. What is the radius of hydrogen? 53pm Notice that the radius is measured in picometers (pm). A picometer is one trillionth of a meter. This study source was downloaded by from CourseH on :03:10 GMT -05:00 This study resource was shared via CourseH GIZMOS Periodic Trends Gizmo Answers Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved Question: What factors affect the radius of an atom? 1. Predict: How do you think the radius of an atom will change as you move down a group (vertical column) in the periodic table? 2. Collect data: Use the ruler to measure the atomic radii of the group 1 elements. As you do so, count the energy levels (shown as rings of electrons) in each atom. Record in the table. 3. Observe: What happens to the radius as you move down group 1? 4. Explore: Turn off Show ruler. Select Li, and then select Be. Observe the radii of the elements in group 2. Then look at other groups. What pattern do you see? 5. Draw a conclusion: In general, what is the effect of the number of energy levels on the radius of an atom? 6. Predict: How do you think the radius of an atom will change as you move across a period (horizontal row) in the periodic table? 7. Collect data: Beginning with Na, record the number of energy levels, number of protons, and atomic radius 2. On the right side of the Gizmo, select Li. Connect the right side of the ruler to the outermost electron, or valence electron. What is the radius of lithium? 167 pm Activity A: Atomic radius Get the Gizmo ready: ● Check that Atomic radius is selected from the drop-down menu. The atomic radius will increase Element H Li Na K Rb Cs Number of energy levels 1 2 3 4 5 6 Atomic radius (pm) 298 In increases That the nucleus is getting bigger and the electron sells gets smaller The atomic radius increases as the group and energy levels increases The atomic radius decreases as you move across the period This study source was downloaded by from CourseH on :03:10 GMT -05:00 This study resource was shared via CourseH for each element in period 3. 8. Observe: What happens to the radius as you move across a period? Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved 9. Explore: Investigate other periods in the periodic table. Does the same trend occur? 10. Analyze: Consider how the number of protons might affect the size of the electron cloud. 11. Extend your thinking: The Gizmo enables you to examine ions, or atoms that have gained or lost electrons. Select Na and turn on Show ion. Compare the radius of the neutral atom to that of the ion. Repeat with Cl. Then look at other ions. See if you can find a pattern. Element Na Mg Al Si P S Cl Ar Number of energy levels 3 3 3 3 3 3 3 3 Number of protons 16 17 18 Atomic radius (pm) 88 79 71 It gets smaller Does the same trend occur? yes Hypothesize why this trend occurs. There is a stronger force of attraction pulling the electrons closer to the nucleus which makes a smaller atomic radius. A. As you move across a period, are new energy levels added? no B. What happens to the number of protons in the nucleus as you move from one element to the next across a period? It is adding one C. If the proton number increases while the number of energy levels remains constant, what happens to the attractive force between the nucleus and the electrons? The attractive force increases D. How does your answer to the previous question explain the trend in radii across a period? As protons are added the attractive force increases, this makes the radium smaller. A. Why do you think the Na + ion is smaller than a neutral Na atom? Na is smaller because it has lost an electron and energy level B. Why do you think the Cl - ion is larger than a neutral Cl atom? Cl is larger because it gained an electron and became stable This study source was downloaded by from CourseH on :03:10 GMT -05:00 This study resource was shared via CourseH Unlike neutral atoms, ions have a different number of electrons than protons. The electrons are attracted to the protons and repelled by other electrons. If another electron is added, the repulsion between electrons increases while the attractive force of the nucleus stays the same. As a result, the electron cloud expands. If an electron is lost, the cloud is pulled in more tightly. Electron repulsions decrease while the number of protons remains constant. Reprduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved Question: How does the radius of an atom affect the ability of the protons in the nucleus to hold on to and attract electrons? 1. Predict: Ionization energy (IE) is the energy required to remove an electron from an atom. As atomic radius increases, the valence electrons get farther from the nucleus. How do you think an atom’s size will affect its ability to hold on to its valence electrons? Why? 2. Investigate: Select H. In the Gizmo, the hydrogen atom is shown next to a positive charge. As you move the atom to the right, the force of attraction between the positive charge and the valence electron will increase until the electron is removed. Slowly drag the atom towards the charge. After the electron is removed, use the ruler to measure the distance between the original and the final position of the electron. Record the distance and ionizatio