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Multiple Choice
Gold has atomic number 79. How many neutrons are in an atom of the most common isotope, with mass number 197?
A
B
C
D
Verified step by step guidance
1
Identify the atomic number (Z) of gold, which is given as 79. The atomic number represents the number of protons in the nucleus of the atom.
Recognize that the mass number (A) of the most common isotope of gold is 197. The mass number is the total number of protons and neutrons in the nucleus.
Recall the relationship between mass number, protons, and neutrons: \(A = Z + N\), where \(N\) is the number of neutrons.
Rearrange the formula to solve for the number of neutrons: \(N = A - Z\).
Substitute the known values into the equation: \(N = 197 - 79\), which will give the number of neutrons in the most common isotope of gold.