# What is the decay equation of cesium 137?

##### 1 Answer

Apr 2, 2016

#""_ 55^137Cs -> ""_ 56^137Ba + ""_"-1"^0beta#

#### Explanation:

Cesium-137 has an atomic number of 55, so is written as

It is also a

Protons and neutrons have the same mass, so the mass number doesn't change. The atomic number increases by one, because one more proton is formed.

Because the atomic number changes, this is a new element, number

In the form of an equation, this is written as

#""_ 55^137Cs -> ""_ 56^137Ba + ""_"-1"^0beta#

This video shows a sample of Cs-137 being tested by a hand-held detector.