Will We Ever Finish the Periodic Table?

Summary

This video explores the idea that while the periodic table might seem complete with 118 elements, it may still have room for more. Early predictions, including those from chemists like Elliot Quincy Adams and physicist Richard Feynman, suggested limits to how many elements could exist. However, modern calculations propose that even larger elements—possibly up to element 173—could be created. Despite their instability, scientists hope to find 'islands of stability,' where certain superheavy elements could last longer, providing new insights into the potential size of the periodic table.

Takeaways

• 🔬 The periodic table looks full, but it's not necessarily complete, as more elements may be discovered beyond the current 118.
• 📈 Chemist Elliot Quincy Adams predicted in 1911 that no element could have an atomic weight larger than 256.
• ⚛️ Back then, elements were classified by atomic weight, but today we classify them by atomic number, which refers to the number of protons in the nucleus.
• 📜 Adams' prediction was proven incorrect, as we’ve since discovered elements with atomic numbers greater than 100.
• 🧑‍🔬 Richard Feynman predicted that an atom with 137 protons would violate special relativity, suggesting it would be the last possible element.
• 💡 Feynman’s calculations might be wrong, as they treated the nucleus as a single point; newer calculations push the limit to 173 protons.
• 🚀 Electrons would have to move faster than the speed of light in atoms larger than 173 protons, which might mark the end of the periodic table.
• ⏳ Heavier elements become increasingly unstable, existing only for fractions of a second before decaying.
• 🏝 Physicists predict ‘islands of stability,’ where certain heavier elements could be more stable and last longer than expected.
• 🔍 The first island of stability could start around atomic number 122 or 126, which may reveal more about how large the periodic table can grow.

Q & A

Why is the periodic table not considered 'complete' even though all elements up to 118 have been discovered?

The periodic table is not considered 'complete' because there could still be more elements beyond 118. Physicists anticipate the possibility of additional rows, as no one is certain how many more elements can exist.

Who was the first person to propose a limit on the size of atoms, and what was their reasoning?

Elliot Quincy Adams was the first to propose a limit on atom size in 1911. He predicted that no element could have an atomic weight larger than 256, equivalent to an atomic number of 99 or 100. His reasoning was based on atomic weights because protons hadn’t been discovered yet.

How did scientists organize elements before protons were discovered?

Before the discovery of protons, scientists organized elements by their atomic weights, which is the sum of the protons and neutrons in the nucleus. At that time, there was no single universal periodic table, and various tables arranged the elements in different ways.

What was Richard Feynman’s prediction about the limit of the periodic table, and why did he believe this?

Richard Feynman predicted that atoms with 137 or more protons would violate the laws of special relativity. He calculated that the electrons in such atoms would need to move faster than the speed of light to stabilize the atom, which is impossible.

Why might Richard Feynman's prediction about the limit of the periodic table be incorrect?

Feynman's prediction may be incorrect because he treated the nucleus as a single point. This works for smaller nuclei but not for larger ones. When the size of the nucleus is taken into account, the limit increases to an atomic number of 173.

What is the significance of element 137, and why might it be humorously named 'Feynmanium'?

Element 137 is significant because Feynman predicted it as the upper limit of the periodic table. Scientists have humorously suggested naming it 'Feynmanium' in honor of Feynman, despite his prediction being potentially incorrect.

What is the adjusted potential limit for the periodic table based on newer calculations?

Newer calculations that account for the size of the nucleus suggest that the periodic table might end at element 173, as atoms with more than 173 protons may require electrons to move faster than the speed of light.

Why do larger elements become more unstable, and how does this affect the possibility of discovering new elements?

Larger elements become more unstable due to the increasing difficulty in holding the protons and neutrons together in the nucleus. As their atomic number increases, they exist for only a fraction of a second before decaying, making it harder to discover and study new elements.

What are 'islands of stability,' and why are they important in the search for new elements?

'Islands of stability' refer to predicted sets of elements that might be much more stable than other superheavy elements. These elements, due to the arrangement of their protons and neutrons, could last much longer than expected, potentially existing for days or years. They are important because they could extend our understanding of the periodic table.

Where might the first 'island of stability' be located on the periodic table, according to predictions?

Predictions suggest that the first 'island of stability' might occur around elements with atomic numbers 122 or 126. Since we've already discovered elements up to 118, scientists believe we are close to reaching this island.