I believe it would be a musical note
Because Na⁺ ion lacks an electron and O²⁻ has two extra electrons extra, to balance the charge, we need 2 Na⁺ ions.
All ions, atoms and molecules want to get to the minimum energy state, and that state is when the ion, atom, or molecule is neutral, that's why all of them want to balance their charges.
The nebular hypothesis is the name of the theory where gravitational attraction caused bits of matter to collapse, eventually forming a solar system.
Hope this helps :)