An atom has a small central nucleus with protons and usually neutrons. Electrons are found around that centre. The number of protons tells us which element it is. Changing only the neutrons makes a different isotope of the same element. Changing electrons changes charge, not the element's proton-based identity.
Matter and chemistry · Discover & try
What makes one atom a different element?
Reading level 1 of 5 · EarlyChange
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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