For nuclei crammed with 100-plus protons, a special type of physics takes center stage. Electrons zip around these giant nuclei, sometimes surpassing 80 percent the speed of light. According to Einstein’s special theory of relativity, when particles move that fast, they seem to gain mass. That property changes how closely the electrons hug the nucleus, and as a result, how easily the atoms share electrons to produce chemical reactions. In such atoms, “relativity rules, and standard common wisdom breaks down,†says nuclear physicist Witold Nazarewicz of Michigan State University in East Lansing. “We have to write new textbooks on those atoms.â€
Getting heavy
The nucleus of superheavy oganesson has 118 protons and many neutrons (blue and red). Its 118 electrons (green) surround the nucleus. Carbon, which is much lighter, contains just six protons and six electrons (not to scale).
T. TIBBITTS
Some of the periodic table’s more familiar elements are already affected by special relativity. The theory explains why gold has a yellowish hue and why mercury is liquid at room temperature (SN: 2/18/17, p. 11). “Without relativity, a car would not start,†says theoretical chemist [Pekka Pyykkö of the University of Helsinki. The reactions that power a car battery depend on special relativity.