Troxler 3241-C - Figure 9. Diagram of an Atom

Model 3241 Series
Appendix A-3
Figure 9. Diagram of an Atom
Protons carry a positive charge and are described as having a
mass of one. Neutrons have a neutral charge and have a mass of
one. Electrons carry a negative charge and essentially have no
mass.
Mass (Atomic Weight Scale)
Charge
Protons 1.0073
+1
Neutrons 1.0087
0
Electrons 0.0006
-1
Because protons and neutrons are clustered together in the
nucleus, the mass of an atom is concentrated in the nucleus. The
atom below has two protons and two neutrons; therefore, it is a
helium atom. The atomic weight of an atom is the sum of the
protons and neutrons.