How do you calculate the atomic mass of an element?

Answer 1

If you know the mass of one mole of those atoms (the mass number listed on the Periodic Table), then you divide that number by Avogadro's constant: 6.022x10^23 which gives you the mass of one single atom

Answer 2

The Atomic Mass can be calculated by adding the mass of protons, neutrons, and electrons. Electrons essentially have no mass, and protons and neutrons have an atomic mass of one. So looking at a common element of oxygen with 8 protons, 8 neutrons, and 8 electrons, we can find the atomic mass to be 16 (the number of protons plus the number of neutrons). An isotope of oxygen having 8 protons, 7 neutrons, and 8 electrons, would have an atomic mass of 15.

Answer 3

- take your average mass and round it, then take your atomic number and subtract it by your average mass. This will give you you atomic mass of an element. -

Answer 4

The mass of an atom is the sum of masses of neutrons, protons and electrons.