SHELL = general energy level of e- in atom. how far its from nucleus. eg n=1 n=2. contains subshells which increases w n. "floor" in a building, each floor has "rooms" (subshells).
SUBSHELL = division of a shell, specific energy levels n shapes. "rooms" on a floor (shell), types spdf.
ORBITAL = specific region within subshell where e- most likely found. Orbitals are labeled by their orientation and shape, and each can hold a maximum of two electrons. (goes up in 1,3,5,7). eg. s orbital - spherical; 1 per shell. p orbitals - Dumbbell-shaped; 3 p orbitals per p subshell.