Summary

In this activity, students will view an animation that explores the shapes of the 1s, 2s, 2p, 3s, 3p, 4s, and 3d orbitals and how they build up and overlap as each successive orbital is added.

Grade Level

High School

NGSS Alignment

This activity will help prepare your students to meet the following scientific and engineering practices:

• Scientific and Engineering Practices:
  • Developing and Using Models

Objectives

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

• Identify the shape of, label, and put in order the 1s, 2s, 2p, 3s, 3p, 4s, and 3d orbitals.
• Identify patterns in the system of numbers and letters used to differentiate between orbitals.

Chemistry Topics

This activity supports students’ understanding of:

• Orbitals
• Electrons
• Atomic structure

Time

Teacher Preparation: minimal
Lesson: 10-30 minutes

Materials

• Computer and projector with internet access
• https://teachchemistry.org/classroom-resources/orbitals-animation
• Student handout

Safety

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

Teacher Notes

• All of the animations that make up the AACT Animation collection are designed for teachers to incorporate into their classroom lessons. Intentionally, these animations do not have any spoken explanations so that a teacher can speak while the animation is playing and stop the animation as needed to instruct.
• If you assign this to students outside of class time, you can create a Student Pass allowing students to view the animation (or any other video or ChemMatters article on the AACT website).
• We suggest that a teacher pause this animation at several points or watch it more than once to give students the opportunity to make notes, ask questions, and test their understanding of the concepts presented. The animation is about one and a half minutes long and moves quickly, so students will likely require pausing or multiple viewings to successfully complete the student activity sheet if you choose to use it. It would probably be easiest to encourage students to focus on answering question 1 (labeling the orbitals) during the first watching and then question 2 (listing the orbitals in order) when watching it a second time. Questions 3 and 4 can be answered using the labeled diagram from question 1 as a reference or during another viewing.
• Use this animation to help students to visualize what the different orbitals look like and how they layer on top of one another as more orbitals are added with increasing energy levels. Students would likely benefit most from this animation if they have already been introduced to the concept of orbitals and their general shapes. Then the animation is used to show how the orbitals all fit together. It shows the orbitals up through 3d in the order in which they fill: 1s, 2s, 2p, 3s, 3p, 4s, 3d.
• Note that when the 2p and 3p orbitals are first shown (0:17 and 0:25), all three orbitals are shown on the same set of x-y-z axes, but they appear one after another rather than all at once to indicate that they are distinct orbitals. Because the d orbitals are more complicated, the five 3d orbitals are shown on separate axes (0:38) so students can see the shape of each one before they fly in to superimpose on each other at the origin of the axis (0:45).
• To communicate their shapes more clearly, orbitals are often represented as three-dimensional shapes with distinct edges, as they are in this animation. In reality, the orbitals are probability distribution maps of where the electrons are most likely to be found, and there are no true hard outer edges. To make the shapes easier to visualize and understand, illustrations representing orbital shapes are often drawn with distinct edges at the point where there is a 90% probability (sometimes 95%) of finding the electron in question within that boundary. Consider the following example of a 2p_x orbital as a probability distribution map, then with the dashed borders marking the 90% probability, then with the shape commonly printed in illustrations:

• The shape of the orbitals corresponds to the sublevel (s, p, or d), and the color of the orbitals corresponds to the energy level (1, 2, 3, or 4). If students have trouble differentiating between colors, they may need assistance with question 3, which asks about the different colored orbitals. It would also be helpful if the student handout were printed in color so the colors on the screen will be the same as the screenshot they are asked to label in question 1.
• Questions 3 and 4 give students an opportunity to think about what the different numbers and letters in the orbital labels (and eventually, electron configurations) mean. They should recognize that all “s” orbitals have the same shapes but different sizes, and all “3” orbitals have the same color in this animation, and approximately the same size (though different shapes), which represents that they are all on the same energy level.
• The extension questions ask students to think about the bigger picture of atoms, electrons, and energy. There is not necessarily a “right” answer to these but they are a good opportunity for the teacher to use this as a formative assessment, gauging how students are thinking about these complex topics in order to help address any possible misconceptions.
• Related classroom resources from the AACT Library that may be used to further teach this topic:
  • Unit Plan: Atomic Structure Unit Plan
  • Activity: Electrons and Orbitals
  • Activity: Planet P-10
  • Lesson Plan: Quantum Numbers
  • Activity: Electron Configuration and the Periodic Table
  • Activity: Electron Configuration and Orbital Diagrams
  • Activity: Bohr Model vs. Quantum Mechanical Model