An isotope retains an element's proton number while differing in neutron number. An ion has unequal proton and electron counts, producing net electric charge. Those two changes should not be confused. The builder reports identity and charge for selected counts but does not predict whether a chosen nucleus is stable or whether a particular ion commonly exists.
Matter and chemistry · Discover & try
What makes one atom a different element?
Reading level 4 of 5 · FluentChange
Word help
atomic number
The number of protons in a nucleus.
isotope
Atoms of one element with different neutron counts.
Watch · Try · Explain
See how it works
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Symbolic atom counts and electron cloud, not size, trajectories, nuclear stability or common-ion prediction.
What to look for
- Protons identify the element
- Neutrons change the isotope
- Electrons change net charge
Explain what you noticed
An atom has 6 protons and 6 electrons. Two neutrons are added. What remains unchanged?
Keep this idea: Protons determine the element; neutrons and electrons have different roles.
Follow the sources
- American Chemical Society — Protons, Neutrons, and Electrons
- American Chemical Society — The Periodic Table
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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