Answer:
The mass number of an atom represents the sum of its protons and neutrons. In the case of iridium (Ir), which has a mass number of 193, the number of protons is equal to the atomic number, which is 77.
Step-by-step explanation:
To find the number of neutrons, subtract the number of protons from the mass number:
Number of neutrons = Mass number - Atomic number = 193 - 77 = 116
Therefore, an atom of iridium with a mass number of 193 has 116 neutrons