The nucleus is very small compared to the atom as a whole: as electrons are even smaller, most of an atom is empty space the diameter of a nucleus can be 100,000 times less than the diameter of an ...

An element's atomic number defines it. An element with 17 protons will always be chlorine. However an element's mass numbers can vary, which means that it can have different numbers of neutrons ...

Single-atom catalysts are defined by their structure where single atoms are dispersed on a suitable substrate, maximizing the exposure of active sites. Unlike nanoparticles or bulk materials, SACs ...