Measurement of the atomic mass gives you the mass of the nucleus, which is directly related to the total number of nucleons (protons and neutrons). And chemical properties of the atom give information about the structure of its electron shells, from that you may extract the number of electrons. The number of protons must be equal to the number of electrons, because atoms are electrically neutral. So you can determine all three numbers.
To be precise, chemistry gives you only an average atomic mass. Many chemical elements have several isotopes, that differ only by the number of neutrons, chemistry would give you in such case only the average of the isotope mass, weighted by its abundance. Mass spectrometry allows to determine the mass (and thus number of neutrons) in each isotope separately.
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to calculate the numbers of subatomic particle in an atom, use its atomic number and mass number:-> number of protons = atomic number, number of electrons = atomic number
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Answer:
Measurement of the atomic mass gives you the mass of the nucleus, which is directly related to the total number of nucleons (protons and neutrons). And chemical properties of the atom give information about the structure of its electron shells, from that you may extract the number of electrons. The number of protons must be equal to the number of electrons, because atoms are electrically neutral. So you can determine all three numbers.
To be precise, chemistry gives you only an average atomic mass. Many chemical elements have several isotopes, that differ only by the number of neutrons, chemistry would give you in such case only the average of the isotope mass, weighted by its abundance. Mass spectrometry allows to determine the mass (and thus number of neutrons) in each isotope separately.