Relativity, Quantum Mechanics, and Complex Electron Orbitals

Yesterday, we said that the simple atomic model shown in older chemistry textbooks leaves many mysteries unanswered. During my 50 years of teaching chemistry, students sometimes asked questions that could not be explained by electrons in circular orbits. In recent years, spectral analysis has shown that electrons travel in various orbital patterns that may be dumbbell or clover-leaf shaped. In addition, quantum mechanics has shown that electrons can act like waves rather than particles. Relativity, quantum mechanics, and complex electron orbitals explain some of the mysteries of chemistry.

For example, oxygen has a first shell with two s-type electrons traveling in circular orbits and four more in dumbbell-shaped p orbits. That second shell can hold six electrons, leaving openings for two more orbitals 90 degrees apart. If a hydrogen atom with one electron comes nearby, it will bond with the oxygen, each of them sharing an electron. If two hydrogens bond with the oxygen atom, you have a perfect, stable combination – a water molecule. 

In the water molecule, the hydrogen atoms repel each other, creating a 180-degree angle between them and giving the water an electrical polarity. The result is that water molecules have a positive and negative end, and as they freeze, they repel each other, expanding their volume. Because of that, ice is less dense and floats on top of the water instead of sinking to the bottom. If bodies of water froze from the bottom up, life on Earth would be impossible.

What makes this picture even more interesting is that electrons can orbit at a speed that is 60% of the speed of light or faster. At that speed, their mass increases, and their orbit contracts in conformity with Einstein’s relativity equations. Relativity, quantum mechanics, and complex electron orbitals combine to explain the mysteries of chemistry. For example, the relativity contraction makes it harder for mercury atoms to interact strongly with each other. As a result, mercury is a liquid, while other metals are solids at room temperature. 

Relativity and quantum mechanics also explain the difference in color between gold and silver. Relativistic effects in the electron orbitals cause silver to reflect all wavelengths of visible light equally. Because of that, it has no particular color. On the other hand, gold’s electron orbitals cause it to absorb blue light, making the reflected light appear yellow. 

Relativity, quantum mechanics, and complex electron orbitals are opening new understandings in chemistry, allowing new techniques to aid in improving life for all humans. For example, doctors use radioactive technetium and rhenium as tracer molecules in medical imaging because of the effects of relativity. Understanding relativity and electron orbitals explains the formation of lead dioxide, which is essential for lead-acid auto batteries. Relativity in electron orbitals even plays a role in “glow-in-the-dark” items such as signs, stickers, and T-shirts.

The complexity of atoms is a testimony to the intelligence and engineering of the Creator. We are continually reminded that we can know there is a God through the things He has made. The challenges and the future of relativistic chemistry are a great testimony to that. 

— John N. Clayton © 2023

Reference: “Relativity and the World of Molecules” by Abhik Ghosh and Kenneth Ruud in American Scientist magazine for May/June 2023