Atomic number and Orbitals 1. Does the amount of protons define the atom? The other subatomic elements just seem to distort the properties on a much smaller scale: electrons seem to only change the charge, and neutrons the stability. Basically I just need the atomic number to define an atom, right? 2. In the following image, the red circle in A contains what is defined as being an orbital, and B a subshell, right? Thanks in advance.