7 Aug 2018

Counting Orbitals: There are rules, it is symmetric, it is beautiful and easy

Five Slides About

Submitted by Joseph Lomax, U.S. Naval Academy
Categories
Corequisites: 
Prerequisites: 
Course Level: 
Description: 

Rules for quantum numbers are confusing but not arbitrary.  They are based on wave mathmatics, and once laid out properly are symmetric and beautiful.  Within four animation-clicks of the first slide of this PowerPoint Presentation, this beauty will unfold.  I do not exaggerate to say, faculty members will be agape and students will say, "Why didn't you show us this before."  No other presentation shows in as elegant a way the relationship between 1)  n, l and ml, 2) the ordering of orbitals in hydrogen-like atoms, and 3) the ordering of orbitals in the periodic table (along with the difficulty of assigning orbital filling in transition and f-block elements).  

Beauty is in every atom.  Let it loose.

Learning Goals: 

A student will be able to relate the quantum numbers n, l and ml to each other.

A student will be able to correctly describe the number of subshells and number of orbitals in a shell.

A student will be able to describe the orbital energies in a hydrogen-like atom.

A student will be able to order subshells in a multi-electron system and relate this to the periodic table.

A student will realize the symmetry and beauty of quantum chemistry without ever seeing the shape of one orbtal.  

Implementation Notes: 

In the first two slides, often use the phrase "because it's a square."

This is useful for Inorganic Chemistry students as well because it will cement in their mind long lost rules of quantum numbers.

 

Evaluation
Evaluation Methods: 

1) Short answer quiz questions

2) Multiple choice questions on hour and final exams.

3) Awe.

Evaluation Results: 

1) From a quiz killer to a typical A, B, C student gets it right, the D student is still a bit confused and the F student still misses the idea.

2)  On a question asking, "how many orbitals in the n=3 shell", the results increased from the 40's to 80's %.  

3) As jaws dropped, quarters could be slipped into their mouths.  Faculty pulled out phones to take pictures of a white-board version before I told them I had a PowerPoint version.

Creative Commons License: 
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