Which produces barium-137 when it undergoes gamma decay? a. cesium-137 b. cesium-138 c. barium-137 d. barium-138

C. Barium-137

Explanation:

We have barium-137

Required to identify the radioisotope that undergoes gamma decay to produce Ba-137.

We need to know that when a radioisotope undergoes gamma decay its mass number and the atomic number remains unchanged.

The atomic number of Ba-137 is 56 while the mass number is 137.We need to identify the choice whose atomic number is 56 and mass number is 137.

In this case,

Cesium-137 has a mass number 137 and atomic number 55Cesium-138 has a mass number 138 and atomic number 55Barium-137, has a mass number, 137 and atomic number 56.Barium-138 has a mass number 138 and atomic number 56

Therefore the correct choice is C. Barium-137