Question

thallium-201 is a radioactive isotope used in the diagnosis of coronary artery disease. what is the mass number of the ti-201 isotope with the symbol \\(\ce{^{201}_{81}tl}\\)? \\(\boldsymbol{13}\\) \\(\boldsymbol{81}\\) \\(\boldsymbol{204.4}\\) \\(\boldsymbol{201}\\)

Explanation:

Step1: Recall Isotope Naming

Isotopes are named with the element symbol followed by the mass number (total protons + neutrons). For \( \ce{Tl-201} \), the "201" is the mass number.

Step2: Identify Mass Number

The isotope is Thallium - 201 (\( \ce{^{201}_{81}Tl} \)), so the mass number is 201.

Answer:

201