Many hospitals use radioisotopes for diagnosis and treatment or in palliative care. Three radioisotopes used in medicine are given. Write the isotope symbol for each radioisotope. Replace the question marks with the proper integers. Replace the letter X with the proper element symbol.

The question is incomplete, here is the complete question:

Many hospitals use radioisotopes for diagnosis and treatment, or in palliative care (relief of symptoms such as pain). Some radioisotopes used in medicine are listed below. Write the isotope symbol for each radioisotope. Replace the question marks with the proper integers. Replace the letter X with the proper element symbol.  

a) Iodine-131:

b) Iridium-192:

c) Samarium-153:

For a: The isotopic representation of the given isotope is:

For b: The isotopic representation of the given isotope is:

For c: The isotopic representation of the given isotope is:

Explanation:

The isotopic representation of an atom is:

where,

Z = Atomic number of the atom

A = Mass number of the atom

X = Symbol of the atom

For the given options:

Option a:  Iodine-131

The atomic number of iodine is 53 and the atomic mass of the given isotope is 131. The chemical symbol for iodine element is 'I'

Hence, the isotopic representation of the given isotope is:

Option b:  Iridium-192

The atomic number of iridium is 77 and the atomic mass of the given isotope is 192. The chemical symbol for iridium element is 'Ir'

Hence, the isotopic representation of the given isotope is:

Option c:  Samarium-153

The atomic number of samarium is 62 and the atomic mass of the given isotope is 153. The chemical symbol for iridium element is 'Sm'

Hence, the isotopic representation of the given isotope is:

the answer is b. dilution