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Periodic Trends Investigation Mark as Favorite (99 Favorites)

ACTIVITY in Periodic Table, Atomic Radius, Ionization Energy, Electron Affinity. Last updated October 03, 2024.

Summary

In this activity, students investigate trends in atomic radius, electron affinity, and ionization energy using an online interactive periodic table

Grade Level

High school

AP Chemistry Curriculum Framework

This activity supports the following unit, topics and learning objectives:

  • Unit 1: Atomic Structure and Properties
    • Topic 1.5: Atomic Structure and Electron Configuration
      • 1.5.A: Represent the electron configuration of an element or ions of an element using the Aufbau principle.
    • Topic 1.7: Periodic Trends
      • 1.7.A: Explain the relationship between trends in atomic properties of elements and electronic structure and periodicity.

Objectives

By the end of this lesson, students should be able to

  • explain the trends in atomic radius across rows and down columns of the periodic table.
  • explain the trends in electron affinity across rows and down columns of the periodic table.
  • explain the trends in ionization energy across rows and down columns of the periodic table.
  • explain the relationships between the above periodic trends.

Chemistry Topics

This lesson supports students’ understanding of

  • Trends of the periodic table
  • Atomic radius
  • Electron affinity
  • Ionization energy

Time

Teacher Preparation: No Time

Lesson: 2.5 hours

Materials

  • Laptop with internet access
  • Graph of atomic radius vs atomic number
  • Graph of ionization energy vs atomic number
  • Chart of first, second, and third ionization energies

Safety

There are no special safety considerations for this activity.

Teacher Notes

The tables and graphs needed for this activity can usually be found in a chemistry textbook

For the Student

Lesson

In this activity, you will discover the periodic trends of atomic radius, ionization energy, and electron affinity.

Answer the following questions before beginning this investigation.

  1. Describe the trends you are aware of that exist on the periodic table.
  2. Define atomic radius, ionization energy and electron affinity.

ATOMIC RADIUS

Use the interactive periodic table found at www.chemicool.com to help you answer the following questions:

  1. Find the atomic radius of the first three elements in rows two, three, and four. Record them below.
  1. What appears to be the trend in the atomic radius as you move left to right across a period?
  2. What appears to be the trend in the atomic radius as you move from top to bottom down a column?
  3. Predict the atomic radii of C, N, Si, P, Ti, and V using the trend you described in question two. Check the actual values using the interactive periodic table. How well do your predictions match the actual values?
  4. Predict the atomic radii of Rb, Cs, Sr, and Ba using the trend you described in question three. Check the actual values using the interactive periodic table. How well do your predictions match the actual values?
  5. Categorize the trend in atomic radius as generally true or absolutely true. Defend your categorization with evidence.
  6. Look at a graph of atomic radius vs. atomic number. How well do the trends you observed match the graph?
  7. Create a hypothesis to explain the trend across a period (row).
  8. Create a hypothesis to explain the trend within a group (column).

IONIZATION ENERGY

Use the interactive periodic table found at www.chemicool.com to help you answer the following questions:

  1. Find the first ionization energy of the first four elements in rows two, three, and four.
  1. Find the first ionization energy of the first four elements in rows two, three, and four.
  2. What appears to be the trend in the first ionization energy as you move left to right across a period?
  3. What appears to be the trend in the first ionization energy as you move from top to bottom down a column?
  4. Predict the first ionization energy of N, O, P, S, V, and Cr using the trend you described in question two. Check the actual values using the interactive periodic table. How well do your predictions match the actual values?
  5. Predict the first ionization energy of Rb, Cs, Sr, and Ba using the trend you described in question three. Check the actual values using the interactive periodic table. How well do your predictions match the actual values?
  6. Categorize the trend in ionization energy as generally true or absolutely true. Defend your categorization with evidence.
  7. Look at a graph of ionization energy vs. atomic number. How well do the trends you observed match the graph?
  8. Create a hypothesis to explain the trend across a period (row).
  9. Create a hypothesis to explain the trend within a group (column).
  10. Define second and third ionization energy.
  11. Look at a chart of first, second, and third ionization energies. Describe how the first, second, and third ionization energies compare to one another. Create a hypothesis to explain your observations.
  12. Examine the changes in ionization energy that take place as an atom goes from an electron configuration of a noble gas to an electron configuration of a halogen. How does the increase in ionization energy compare to other increases?

ELECTRON AFFINITY

Use the interactive periodic table found at www.chemicool.com to help you answer the following questions:

  1. Find the electron affinity of elements in rows two, three, and four. Keep looking up values until you think you have enough information to answer questions two through six.
  2. What appears to be the trend in the electron affinity as you move left to right across a period?
  3. What appears to be the trend in the electron affinity as you move from top to bottom down a column?
  4. Categorize the trend in electron affinity as generally true or absolutely true. Defend your categorization with evidence.
  5. Create a hypothesis to explain the trend across a period (row).
  6. Create a hypothesis to explain the trend within a group (column).

Analysis

  1. Sketch a periodic table. Draw two color coded arrows for each of the trends you investigated showing the direction in periods and in rows the values increase.
  2. Which trends are directly correlated and which are inverses of each other? Discuss why certain trends may be correlated and others may be inversely related.
  3. Examine all of your hypotheses. List and describe any unifying ideas you can use to explain all of the periodic trends.