Summary

In this activity, students will learn how the periodic table can be used to predict the electron configuration of an atom and, thus, better predict the reactivity of an atom.

Grade Level

High School

NGSS Alignment

This activity will help prepare your students to meet the performance expectations in the following standards:

• HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms. 

Objectives

By the end of this activity, students should be able to:

• Write the electron configuration of an atom using the Aufbau Principle.
• Correlate the valence orbital of an atom with the atom’s placement on the periodic table.
• Predict the relative reactivity of an atom based on its electron configuration and placement on the periodic table.

Chemistry Topics

This activity supports students’ understanding of

• Electron Configurations
• The Periodic Table
• Aufbau Principle
• Valence electrons
• Electron orbitals
• Subatomic Particles

Time

Teacher Preparation: minimal

Lesson: 45-60 minutes

Materials

• Periodic table, 1 per student
• Post-it notes, 1 per student
• Markers
• Large wall-sized periodic table
• List of 20 atoms

Teacher Notes

• A lesson on writing electron configurations should precede this lesson. This could involve writing configurations in order of orbitals with the aid of an Aufbau chart (see sidebar for a chart through 5p). Once students get the hang of that, this activity will help them recognize how patterns in electron configuration line up with the layout of the periodic table – and that is in fact why the periodic table has its strange shape!
  • A good activity from the AACT resource library to introduce students to the Aufbau principle and electron configurations is Electron Configuration and Orbital Diagrams
  • If your students are more familiar with the Bohr model, Bohr Model vs. Quantum Mechanical Model is a good resource to help them transition to the more modern model.
    
• This lesson involves individual work to practice writing electron configurations, pair work to check electron configurations, and a culminating class activity.
• Students will be instructed and will practice writing electron configurations for 20 carefully chosen atoms: H, Xe, Rb, Fe, Si, I, Hg, Ra, Mg, Eu, Zn, Ta, Ba, N, S, Co, He, Am, Y, Pd.
• It is suggested that lower performing students should be assigned the shorter configurations only (ex: those in the first 3 periods, before the d-block, or those in the first 5 periods, before the f-block) and higher performing students should be assigned all 20 atom configurations.
• Direct students to check their configurations with their shoulder partner and resolve any discrepancies in their answers.
• You will randomly assign each student one atom and from the list of assigned atoms. Students will write the valence shell in large print, with a marker on their post-it note (ex. 4s²).
• The student will place the post-it note on the corresponding element symbol on the large wall-sized periodic table. Students will then study the chart with the post-it-notes and observe any noted trends, relationships to groups and periods, with classmates.
• You could follow up this activity with a fun game of E-config Battleship for more practice with electron configurations!