How do isotopes of carbon differ from one another?

1 Answer
Jul 25, 2014


They differ in the number of neutrons in the nucleus.


Isotopes are atoms that have the same number of protons but different numbers of neutrons.

Carbon has 15 known isotopes, ranging from carbon-8 to carbon-22.

Only carbon-12 and carbon-13 are stable. Carbon-14 is the longest-lived radioactive isotope.

We write the symbols for isotopes as #""_Z^AX#, where #X# is the symbol of the element, #Z# is the atomic number, and #A# is the mass number.

The number of neutrons = #A - Z#.

The symbol for carbon-12 is #""_6^12"C"#. A carbon-12 atom has 12 – 6 = 6 neutrons.

The symbol for carbon-13 is #""_6^13"C"#. A carbon-13 atom has 13 – 6 = 7 neutrons.

The symbol for carbon-14 is #""_6^14"C"#. A carbon-14 atom has 14 – 6 = 8 neutrons.

In the same way, a carbon-8 atom has 2 neutrons, and a carbon-22 atom has 16 neutrons.