The order of placement of the elemnts on the modern Periodic Table is determinated by:
1)atomic number (Z=number of protons).
B)
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a subatomic particle with no electric charge, found in the nucleus of an atom </span>
31
A dalton is the same as an atomic mass unit. And an atomic mass unit is approximately the mass of a nucleon (proton or neutron) such that the mass is 1 g/mol. So in this problem you have 15 protons and 16 neutrons, so the number of daltons is 15 + 16 = 31.
