There was big news in the world of chemistry yesterday when scientists from Japan, the United States and Russia announced the existence of four new superheavy elements that complete the seventh row of the periodic table. The elements have the atomic numbers 113, 115, 117 and 118 in the updated chart above.
It’s big news, I guess, although these elements, which have yet to be named, don’t exist in nature. Instead, they’re created in labs by slamming lighter elements together so they form a new element that exists only briefly before decaying into smaller components.
That process mimics, to a certain extent, how matter is created in the natural world. That’s done via fusion in stars. Hydrogen, being the simplest atom with one proton and one electron, is by far the most common element in universe. Under massive pressure in stellar interiors, hydrogen atoms “fuse” together to produce helium (two protons, two neutrons and two electrons). This fusion reaction produces some sub-atomic particles, along with a whole pile of energy in the form of light, heat and other radiation that, in the case of our Sun, we rely on for life.
Elements further down on the periodic table such as carbon, nitrogen and oxygen are produced through a similar stellar process using combinations of hydrogen and helium atoms. Carbon, for instance, consists of six protons, six neutrons and six electrons.
The further down you go on the periodic table, the heavier the elements get. The heavier the element is, the more difficult it is to produce in nature. Elements such as sulphur (16 protons, 16 neutrons and 16 electrons) and iron (26 protons, 30 neutrons and 26 electrons), for instance, are only created at the end stages of a star’s life when it becomes unstable and gravitational forces are generated that produce sufficient pressure to fuse larger numbers of atomic elements together.
Then you have elements further down on the periodic table such as silver, gold and platinum that are heavier still. Gold, for instance, has 79 protons, 118 neutrons and 79 electrons, and elements like that are typically only created during a nova/supernova explosion that marks a star’s death. Because of those special circumstances, heavy elements are much rarer in the universe than lighter elements. But they do occur naturally.
We’ve produced synthetic elements before, and the four announced yesterday join that list. As you can read in this Guardian report, scientists will likely continue with experiments to produce even heavier synthetic elements which I guess will open up a whole new row on the periodic table — although how far we can go is unknown. Some scientists speculate there’s a theoretical limit with estimates ranging from atomic number 128 to 173. Although synthetic elements larger than that haven’t been ruled out.