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Science
Isotope Notation
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. Their chemistry is very similar, while their masses and nuclear stability can differ. One element can therefore have several nuclear versions without changing its place in the periodic table.
Before going further
Try this
Connect the idea on this page with one concrete situation. Name the quantity, particle or phenomenon involved, then ask what would change if one variable increased while the others stayed fixed.
Use a simple value first. Predict the direction of the result before calculating, then check units and order of magnitude. If the number is surprising, investigate the model before trusting the calculator.