# How do isotopes of carbon differ from one another?

Jul 25, 2014

They differ in the number of neutrons in the nucleus.

#### Explanation:

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 $\text{_6^12"C}$. A carbon-12 atom has 12 – 6 = 6 neutrons.

The symbol for carbon-13 is $\text{_6^13"C}$. A carbon-13 atom has 13 – 6 = 7 neutrons.

The symbol for carbon-14 is $\text{_6^14"C}$. 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.