1 ton
The weight of an atom is primarily determined by the total number of protons and neutrons in its nucleus. Electrons, which have negligible mass, also contribute to the atom's weight but to a much smaller extent.
atom<cell
No region has all the weight, but the vast majority of the mass of an atom is in the nucleus.
An atom of oxygen has twice the weight of an atom of nitrogen since the atomic weight of nitrogen is around 14 amu (atomic mass units), while the atomic weight of oxygen is around 16 amu.
None Even electrons have weight
The number of protons and neutrons controls the weight of an atom.
6
The protons and the neutrons.
Helium atom has 2 protons and 2 neutrons (that accounts for its atomic weight). The atomic weight of helium is 4.00260
Atomic mass
It is 39.948
The total weight of the protons and the neutrons.