# How many empty orbitals do elements have?

A student was contemplating a question regarding elements with "no empty valence orbitals." An argument was made that elements all have infinite number of valence orbitals.

Every atom basically has an infinite number of shells. The thing is that almost all of those shells are empty (they don’t have electrons in them).

https://van.physics.illinois.edu/qa/listing.php?id=1224

So it is facile to say that, say, the fluoride anion has no empty valence orbitals on the basis of it having 8 valence electrons and the $2n^2$ rule (where n = 2)?

• While it's true that electron orbitals could go on forever, each element has to have a practical limit. For example, a hydrogen atom can easily hold 1 electron because it has 1 proton. A hydride can have 2 electrons and a -1 charge. However I don't think you can jam 10 electrons on a hydrogen even if the orbitals technically exist to hold them. I don't know what the best way to describe the number of orbitals on an atom is, but calling it infinite may confuse some students. – user137 Aug 19 '14 at 16:31
• @user137 its important to note that once you have more than 1 electron, the hydrogenic orbitals are an approximation anyway. Though from a simple perspective you could just say that after a certain point those orbitals have a positive orbital energy and that can explain why you wouldn't ever have $\ce{H^{9-}}$. You could access these orbitals by excitations if you only have 1 electron. – Tyberius Dec 14 '17 at 17:12