Final answer:
The atomic mass of gold is (C) 197. This value represents the most stable isotope of gold which has a mass number reflecting the total number of protons and neutrons in the nucleus.
Step-by-step explanation:
The atomic mass of gold (Au) is 197. This value corresponds to the most stable isotope of gold, which has 79 protons (the atomic number) and 118 neutrons, giving it a mass number of 197.
This is a fundamental concept in nuclear chemistry, where both protons and neutrons in an atomic nucleus are conserved during reactions. The total mass number, therefore, remains constant, as shown in balanced nuclear equations.
For example, when examining nuclear processes involving gold, you would use the mass number 197 for calculations.