Answer :
Let's solve the problem step-by-step:
1. Identify Protons:
- The atomic number (lower left number) of gold (Au) is 79. This number tells us the number of protons in the nucleus of an atom of gold.
- Therefore, the number of protons is: [tex]\( 79 \)[/tex]
2. Identify Neutrons:
- The mass number (upper left number) of gold is 197. The mass number is the total number of protons and neutrons in the nucleus.
- The number of neutrons is calculated by subtracting the number of protons from the mass number:
[tex]\[
197 \, \text{(mass number)} - 79 \, \text{(number of protons)} = 118 \, \text{neutrons}
\][/tex]
- Therefore, the number of neutrons is: [tex]\( 118 \)[/tex]
3. Identify Electrons:
- The ion given is [tex]\( \text{Au}^{3+} \)[/tex]. The neutral gold atom has the same number of electrons as protons (79). Since this is a [tex]\( 3+ \)[/tex] ion, it has lost 3 electrons.
- The number of electrons is calculated by subtracting 3 from the number of protons:
[tex]\[
79 \, \text{(number of protons)} - 3 = 76 \, \text{electrons}
\][/tex]
- Therefore, the number of electrons is: [tex]\( 76 \)[/tex]
Putting it all together, the [tex]\( \text{Au}^{3+} \)[/tex] ion has:
- [tex]\( 79 \)[/tex] protons
- [tex]\( 118 \)[/tex] neutrons
- [tex]\( 76 \)[/tex] electrons
So the correct option from the provided choices is:
[tex]\[ 79 p^{+}, 118 n^{0}, 76 e^{-} \][/tex]
1. Identify Protons:
- The atomic number (lower left number) of gold (Au) is 79. This number tells us the number of protons in the nucleus of an atom of gold.
- Therefore, the number of protons is: [tex]\( 79 \)[/tex]
2. Identify Neutrons:
- The mass number (upper left number) of gold is 197. The mass number is the total number of protons and neutrons in the nucleus.
- The number of neutrons is calculated by subtracting the number of protons from the mass number:
[tex]\[
197 \, \text{(mass number)} - 79 \, \text{(number of protons)} = 118 \, \text{neutrons}
\][/tex]
- Therefore, the number of neutrons is: [tex]\( 118 \)[/tex]
3. Identify Electrons:
- The ion given is [tex]\( \text{Au}^{3+} \)[/tex]. The neutral gold atom has the same number of electrons as protons (79). Since this is a [tex]\( 3+ \)[/tex] ion, it has lost 3 electrons.
- The number of electrons is calculated by subtracting 3 from the number of protons:
[tex]\[
79 \, \text{(number of protons)} - 3 = 76 \, \text{electrons}
\][/tex]
- Therefore, the number of electrons is: [tex]\( 76 \)[/tex]
Putting it all together, the [tex]\( \text{Au}^{3+} \)[/tex] ion has:
- [tex]\( 79 \)[/tex] protons
- [tex]\( 118 \)[/tex] neutrons
- [tex]\( 76 \)[/tex] electrons
So the correct option from the provided choices is:
[tex]\[ 79 p^{+}, 118 n^{0}, 76 e^{-} \][/tex]
