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Periodic War Mark as Favorite (97 Favorites)

ACTIVITY in Periodic Table, Atomic Radius, Ionization Energy, Electronegativity. Last updated March 25, 2020.


In this activity, students play a card game to apply their knowledge of the periodic trends of the main group elements.

Grade Level

High School

NGSS Alignment

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

  • Scientific and Engineering Practices:
    • Analyzing and Interpreting Data
    • Engaging in Argument from Evidence


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

  • Determine which element has a larger atomic radius when presented with specific examples.
  • Determine which element has higher ionization energy when presented with specific examples.
  • Determine which element has a larger electronegativity value when presented with specific examples.
  • Explain how a specific periodic trend applies to given element examples.

Chemistry Topics

This activity supports students’ understanding of

  • Periodic Trends
  • Atomic Radius
  • Ionization Energy
  • Electronegativity


Teacher Preparation: 0–30 minutes (see Teacher Notes)

Lesson: 30 minutes


  • 1 set Element Cards per student (available for download)
    • A set of 40 elements cards (elements 1–40) for each player, or
    • Use elements 1–20 (or a smaller selected subset)
  • Access to a periodic table


  • No specific safety precautions need to be observed for this activity.

Teacher Notes

  • Read more about this activity in the article, Teaching Periodic Trends with a Popular Card Game, in the March 2020 issue of Chemistry Solutions.
  • Minimal preparation time is required by the teacher if the task of making the cards is given to the students. Plan for approximately 30 minutes of prep time if the cards are prepared by the teacher.
  • This game is played with small groups of students. 2–3 players per group is recommended, but it is easiest with just 2.
  • The object of the game is to take all the cards from the other players.
  • This game follows the same principles as the traditional card game, War.
  • Directions:
    • Players sit opposite each other with their deck of cards in their hands.
    • Each player has their own set of element cards.
    • A periodic table should be in plain view of all the players for reference.
    • Before the start of the game, the players (or teacher) choose which periodic trend they will play for (the trend can be changed at any time in the game).
    • Each player flips over a card at the same time.
    • The person who wins the cards shown is determined based on the periodic trend that is currently being used.
  • Whenever the elements cards played are in the same period or group, whoever has the higher value for the trend chosen takes all the cards.
  • Sample situation: The periodic trend “Atomic Radius” has been chosen:
    • Example 1: Na and K are the cards turned over by the players. Since they are playing with atomic radius in mind, K wins the hand since K has a bigger atomic radius.
    • Example 2: Three players are playing. Na, K and Mg are the cards turned over by the players. Mg loses automatically, and K wins all three cards because it has the bigger atomic radius.
  • If the elements played are not in the same group or period, then the element with the higher atomic mass wins the hand.
    • Example: Mg and Kr are played. Kr wins because it has a larger atomic mass.
  • If any two cards are the same, then war is declared. Each player lays 3 cards out facedown, then plays the 4th card face-up. Using the rules outlined above, the winner takes all the cards.
    • Example: Mg and Mg are played. Each player lays out 3 facedown cards, then player 1 plays Na, and player 2 plays Sulfur. Player 1 takes all the cards because Na has a larger atomic radius (assuming atomic radius was the trend selected at the time of war).
  • Players should provide explanations of why a certain element wins before taking the cards. The player who takes all the other players’ cards is the winner!
  • A set of 40 element cards are available for download and printing.