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What are isotopes?

Isotopes are variations of chemical elements that have the same number of protons but different numbers of neutrons.

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What are isotopes?

Isotopes are variations of chemical elements that have the same number of protons but different numbers of neutrons.

We identify isotopes based on their mass, whereby the sum of protons and neutrons equals the mass of the isotope.

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What are isotopes?

This carbon atom has a mass of 12:

6 protons + 6 neutrons.

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What are isotopes?

This carbon atom has a mass of 12:

6 protons + 6 neutrons.

The name of this isotope, then, is 12C:

C for carbon, 12 for its mass.

12C

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What are isotopes?

Two other isotopes of carbon exist in addition to 12C. They are:

12C 6 protons

+ 6 neutrons

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What are isotopes?

Two other isotopes of carbon exist in addition to 12C. They are:

12C 13C6 protons

+ 6 neutrons

6 protons

+ 7 neutrons

and…

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What are isotopes?

Two other isotopes of carbon exist in addition to 12C. They are:

12C 13C

14C

6 protons

+ 6 neutrons

6 protons

+ 7 neutrons

6 protons

+ 8 neutrons

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What are isotopes?

12C 13C

14C

6 protons

+ 6 neutrons

6 protons

+ 7 neutrons

6 protons

+ 8 neutrons Since isotopes have distinct masses, we identify C isotopes in our samples by measuring the mass of the carbon atoms. We use an instrument called an isotope ratio mass spectrometer to make these measurements.