Here's why:

* Atomic Number: Francium has an atomic number of 87, meaning it has 87 electrons.

* Electron Configuration: The electron configuration of Francium is [Rn] 7s¹. This means the electrons are distributed across the shells as follows:

* Shell 1: 2 electrons

* Shell 2: 8 electrons

* Shell 3: 18 electrons

* Shell 4: 32 electrons

* Shell 5: 18 electrons

* Shell 6: 8 electrons

* Shell 7: 1 electron

Therefore, Francium has 7 electron orbital shells.