Science The periodic table you grew up with is wrong

The Helper · Jun 14, 2023

Up until 2002, we thought that the heaviest stable element was bismuth: #83 on the periodic table. That's absolutely no longer the case.

As we came to observe the Universe on smaller and more fundamental scales, we began to discover what the building blocks of matter were. Macroscopic materials are made up of smaller components that still retain the physical and chemical properties of the larger original. You can break things down into individual molecules, and still those molecules will exhibit the same behavior in isolation as they did when they were part of the larger structure. Molecules can be broken down further, into individual atoms, which still retain the same binding properties they possessed when they were in molecules: evidence that there’s something very important, on the atomic level, for building up the larger-scale structures in our Universe today.

We eventually came to recognize that atoms have properties that can be sorted, periodically, by the number of protons in their nucleus. The positive charges in the nucleus determine how many electrons must orbit that nucleus to make an electrically neutral atom, and then the behavior of those electrons, according to the laws of quantum physics, determine how those atoms behave, interact, and bind together. The periodic table of elements is taught across schools worldwide. There’s just one problem: if you learned the elements from a periodic table made before 2003, there’s a glaring error within it. Here’s what everybody should know.

Within the core of every atom lies an atomic nucleus: a tightly bound, massive structure composed of at least one proton and, in all cases except one, multiple neutrons as well. While most of the atoms that make up the everyday world we experience are known to be stable, there are many combinations of protons-and-neutrons that are inherently unstable, and will decay away into a different element if enough time is allowed to pass.

For some elements, like carbon, there are multiple stable isotopes, as carbon-12 (with 6 protons and 6 neutrons) is stable, as is carbon-13 (with 6 protons and 7 neutrons). However, you can also have carbon-14, with 6 protons and 8 neutrons, which is not stable, but given enough time, will radioactively decay by emitting an electron, an anti-electron neutrino, and transforming one of its neutrons into a proton: becoming nitrogen-14 in the process. Nitrogen-14, with 7 protons and 7 neutrons in its nucleus, is absolutely stable, as is another isotope of nitrogen: nitrogen-15, with 7 protons and 8 neutrons.