The locations with subatomic particles with the least mass are locations 1 and 4.
An atom is usually divided into two main regions:
The three sub-particles previously mentioned (neutrons, protons, and electrons) differ not only in their location but also in their mass. Indeed, electrons have a lower mass if compared to neutrons and protons.
Based on this, the outer region (locations 1 and 4) has sub particles with the least mass.
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