Yes. density is a physical property that can be used to identify matter
B is true if we subtract atomic number(the number of protons )from the mass number
we can find neutrons.
hope this helps
Schrödinger found the quantum mechanical model of the atom after Bohr’s model.
It is better than Bohr’s model because you can use mathematical equations to find electrons certain position. Unlike Bohr’s which is just a “cloud” where the an electron could possibly be.
