Question

What is the daughter element produced by Technetium-99m (atomic number-43; mass number-99) alter $\gamma$-decay?

• A. ${}_{43}^{98}Tc$
• B. ${}_{42}^{99}Mo$
• C. ${}_{44}^{99}Ru$
• D. ${}_{41}^{95}Nb$
• E. ${}_{43}^{99}Tc$

Answer 1

The correct option is E ${}_{43}^{99}Tc$

Option E is the correct answer.

After a gamma decay, the number of protons and the number of neutrons in the nucleaus of an atom does not change. So the parent and the daughter element remains the same with the same atomic number and the same mass number.

Thus, technetium-99m with atomic number 43 and mass number 99 will remain the same.