# Question #40a52

##### 1 Answer
Nov 1, 2016

Isotones are isotopes that have the same number of neutrons but different numbers of protons.

#### Explanation:

For example, $\text{_5^12"B}$ and $\text{_6^12"C}$ are isotones because they each contain 7 neutrons.

The largest group of stable isotones is

$\text{_56^138"Ba", ""_57^139"La", ""_58^140"Ce", ""_59^141"Pr" , ""_60^142"Nd", ""_62^144"Sm}$

They are isotones because they all contain 82 neutrons