Pretty much any element(in your case sodium) contain these properties.
Atoms can be an ion, but not all ions are atoms. The difference between an atom and an ion has to do with net electrical charge. An ion is a particle or collection of particles with a net positive or negative charge. ... A stable atom contains the same number of electrons as protons and no net charge
It's called buoyancy. It is the tendency of an object to float
So it could follow the correct mass for the atom
When conducting and experiment you want to have a notebook and something to write down notes with so you can keep everything organized and proper, and to not miss anything in the experiment. Also you want to have everything in order of the way it should be in.
I hope you found this helpful!