How to use the isotope neutron count calculator
Count protons, neutrons and electrons of an isotope or ion. Enter atomic number (protons), mass number, ion charge in the fields above; the neutrons, electrons, protons are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- Z — Atomic number (protons)
- A — Mass number
- q — Ion charge
Worked example
With atomic number (protons) = 17, mass number = 35, ion charge = -1, the calculator gives neutrons ≈ 18; electrons ≈ 18; protons ≈ 17.
Frequently asked questions
What is the formula for the isotope neutron count calculation?
Neutrons = A-Z. Electrons = Z-q. Protons = Z. Here Z is atomic number (protons), A is mass number, q is ion charge.
What inputs do I need for the isotope neutron count calculator?
You need atomic number (protons), mass number, ion charge. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.