Question

Determine the number of protons and neutrons for the radioactive atom ${}^{99}{T}_c$.

• A. 43 protons and 56 neutrons
• B. 43 protons and 99 neutrons
• C. 56 protons and 43 neutrons
• D. 56 protons and 99 neutrons
• E. Cannot be determined

Answer 1

The correct option is A 43 protons and 56 neutrons

Technetium-99 has atomic number 43. So, number of protons and electrons are 43. No of neutrons is (mass no - no of protons), $99-43=56$. So, no of protons are 43 and no of neutrons are 56.