« Return to AACT homepage

AACT Member-Only Content

You have to be an AACT member to access this content, but good news: anyone can join!

Need Help?

Planet P-10 Mark as Favorite (35 Favorites)

ACTIVITY in Periodic Table, Covalent Bonding, Ionic Bonding, Electron Configuration, Atomic Radius, Electrons, Orbitals . Last updated December 29, 2022.


In this activity, students will create a periodic table using the unusual orbital rules elements follow on an imaginary planet called P-10 and identify periodic trends.

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.
  • Scientific and Engineering Practices:
    • Developing and Using Models


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

  • Demonstrate an understanding of electron orbitals by creating a periodic table using orbital rules from an imaginary planet.
  • Determine which elements on a periodic table are the most and least reactive.
  • Identify periodic trends.

Chemistry Topics

This activity supports students’ understanding of:

  • Periodic table
  • Orbitals


Teacher Preparation: 15 minutes

Lesson: 45 minutes


  • Student handout


  • No specific safety precautions are needed for this activity.

Teacher Notes

  • Prior to completing this activity, students will need to understand the structure of the periodic table and how electrons fill orbitals (Pauli exclusion principle, Aufbau principle, and Hund’s rule).
  • Note that the scenario for this activity is not based on true events, and remind students that there is no “Planet P-10” in real life! (Also note that when this imaginary scenario took place in 1997, Pluto was still considered a planet, so this new one would have been the 10th planet!)
  • Since these are “imaginary elements” students have to apply the rules of orbital filling in a new way – they might struggle a bit at first, but once it clicks they should be able to make their periodic table and answer questions about it. If they are familiar with where the elements are on the table already, it may be a bit jarring to see them in the “wrong” places, so be ready to encourage them if they get stuck or confused!
  • This activity could be done individually, but it may be helpful for students to be able to discuss their ideas with a partner and could be assigned as a partner activity as well.

For the Student



March 14, 1997 - An amazing discovery was accidentally made by Washington State University astronomers using the Hubble Space Telescope. While probing dust clouds in what they thought was interstellar medium, these astronomers stumbled across a small, previously unknown planet at the farthest edge of our solar system. This planet has yet to be named and is simply known as P-10 (the tenth planet in our solar system). Soon after its discovery, scientists became frantic to learn more about this long-overlooked planet. Plans were soon made to launch a probe in 1999.

October 4, 2021 - It has been several years since data returned from the probe’s survey of P-10 and the WASU scientists are increasingly perplexed. According to information received from the probe, the elemental composition of P-10 was amazingly exotic. If the data was correct, P-10 was constructed of completely new and never before seen elements. Realizing that the enormity of this discovery was beyond their capabilities to explain, the P-10 project scientists decided to consult with astrophysicists from the University of Washington.

October 7, 2021 - At last a breakthrough! After several days of very hard work, the scientists believe they have the answer for the unique elemental structure of P-10. Apparently, a small number of the current quantum mechanical theories do not seem to apply on P-10. For some unknown reason, electron orbitals within atoms on P-10 are confined to spatial orientations which are much more restrictive than those found on Earth. Specifically:

The p orbitals within atoms on P-10 have 2 rather than 3 spatial orientations.

The d orbitals within atoms on P-10 have 3 rather than 5 spatial orientations.

The f orbitals within atoms on P-10 have 4 rather than 7 spatial orientations.

[The s orbitals remain the same (1 spherical orbital on each energy level)]

All other postulates of quantum mechanics are found to be the same on P-10 as they are on earth (the Pauli exclusion principle, the Aufbau principle, Hund’s rule, etc.…)


To communicate the significance of this discovery to other scientists, do the following:

  1. Construct a new periodic table which demonstrates your findings using existing elemental names and atomic numbers. (Hydrogen should still be atomic number one, Helium atomic number two, etc.) This table should include the first 80 elements (Hydrogen through Mercury) and demonstrate the periodic nature of elements on P-10.
  2. Name those elements on P-10 which correspond to noble gases on Earth.
  3. Name those elements on P-10 which correspond to the most active metals on Earth.
  4. Show the trends in atomic radii and give examples within a group and period.
  5. Write the electron configuration of the following atoms on your P-10 periodic table:
    1. F
    2. K
    3. Rb
    4. Ag