Answer: Atomic number is the number of protons
Atomic mass subtract
atomic number is the number of neutrons
Atomic number is the number of electrons in a neutral atom
Explanation:The atomic number is assigned based on the number of protons, so the atomic number is always the same as the number of protonsAtomic mass is the sum of protons and neutrons. Protons and neutrons both have masses of 1 amu, but the mass of electrons is negligible so it is left out. The atomic mass of an element is never a round number because it's a weighted average of all the isotopes of the element. Just round the number to the nearest integer get the most likely atomic mass. In a neutral atom number of protons = number of electrons since there is no overall charge. In an ion, add an electron for every negative charge and subtract an electron for every positive charge (ex. Mg2+ has 10 electrons because its atomic number is 12 and you subtract two electrons for the 2+ charge)