Question

the number of subatomic particles represented by $_{79}^{197}au^{3 + }$: protons neutrons electrons
79 197 79
79 118 79
79 118 76
118 79 76
79 118 82

Explanation:

Step1: Determine number of protons

The atomic number (sub - script) of gold (Au) is 79. The number of protons is equal to the atomic number. So, number of protons = 79.

Step2: Determine number of neutrons

The mass number (super - script) is 197. The number of neutrons is calculated as mass number - atomic number. So, number of neutrons = 197 - 79=118.

Step3: Determine number of electrons

The ion is $\text{Au}^{3 + }$, which means it has lost 3 electrons. A neutral gold atom has 79 electrons. So, number of electrons in $\text{Au}^{3 + }$ is 79 - 3=76.

Answer:

C. 79, 118, 76