According to Rutherford's nuclear theory, most of the volume of an atom is empty space , so the volume of a hydrogen atom cannot be mostly due to the proton.
According to Rutherford's nuclear theory, the core of an atom (nucleus) contains most of the mass of an atom and is positively charged , so the majority of the mass of a fluorine atom cannot be due to its nine electrons.
According to Rutherford's nuclear theory, the number of negatively charged particles outside the nucleus is the same as the number of positively charged particles within the nucleus, so a nitrogen atom has 7 protons and 7 electrons, while a phosphorous atom cannot have 15 protons and 150 electrons.
empty space - Rutherford bombarded with electrons a thin sheet of gold and observed the most the electrons are not deviated, few of them have a change in trajectory and very few had a high deflection angle. From the experiment he concluded that the volume atoms have a lot of empty space.
mass, positively charged - the electrons are deviated by the nucleus which have to be positively charged because it deflects electrons which by definition are negatively charged.
the same as the number - the atom is neutral, so the number of electors are equal to the number of protons.