Answer :
Answer:
It's the second one down.
Explanation:
Gold
Mass 197
Number of Protons: 79
Number of Neutrons: 197 - 79 = 118
Number of electrons: = number of protons = 97
An atom of gold (Au) with a mass number of 197 contains 79 protons, 118 neutrons, and 79 electrons. This is determined based on its atomic number and mass number.
The student has asked how many protons, neutrons, and electrons are present in an atom of gold (Au) with a mass number of 197. According to standard atomic structure, the number of protons in an element is determined by its atomic number, which for gold is 79. Thus, the atom of gold has 79 protons.
Since the mass number is the sum of protons and neutrons, we can calculate the number of neutrons as follows:
Neutrons = Mass number - Atomic number = 197 - 79 = 118
In a neutral atom, the number of electrons equals the number of protons. Therefore, there are 79 electrons in this atom of gold.
Thus, the correct choice is:
- 79 protons, 118 neutrons, and 79 electrons
