Question

what radioactive element has the lowest atomic number? how many of the elements are radioactive?

Explanation:

• For the first question, we know from the periodic table and knowledge of radioactive elements that technetium (Tc) has an atomic number of 43, which is the lowest among radioactive elements.
• For the second question, based on the understanding of the periodic table and radioactive elements, there are 38 radioactive elements.

Answer:

• The radioactive element with the lowest atomic number is technetium (Tc).
• There are 38 radioactive elements.