👉 Subshell, in chemistry and physics, refers to a specific region of a shell (a layer of electrons) within an atom. Subshells are typically defined by their size relative to the nucleus, with each element having its own unique set of subshells. For example, in the atomic number 17, the subshell is designated as "subshell" because it has a size that corresponds to the width of the first valence electron shell. This means that for every additional electron
