Atom/Proton Number and Isotopes

Atom/Proton Number

Each element of a specific element contains the same number of protons, for example all the atoms of carbon have 6 protons in their nucleus.

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Every different element has a different atom number, this idea is used to order the periodic table.

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Isotopes

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All the atoms of a particular element have the same amount of protons. however, the number of protons can vary within the atoms of an element.

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An isotope is the same element with the same number of protons but a different number of neutrons.

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For example the proton number of carbon is 6, so all atoms of carbon have 6 protons but their number of neutrons can differ.

Most carbon  atoms contain 6 protons and 6 neutrons making the mass number (protons + neutrons) 12. However, some carbon atom isotopes also exist with 6 protons and 8 neutrons giving it a mass number of 14.