How many protons, neutrons, and electrons are in this ion?

[tex]\[ { }_{80}^{204} Hg ^{2+} \][/tex]

A. [tex]\( 80 p^{+}, 124 n^0, 78 e^- \)[/tex]

B. [tex]\( 102 p^{+}, 102 n^0, 104 e^- \)[/tex]

C. [tex]\( 80 p^{+}, 124 n^0, 80 e^- \)[/tex]

D. [tex]\( 80 p^{+}, 124 n^0, 82 e^- \)[/tex]



Answer :

Certainly! Let's carefully determine the number of protons, neutrons, and electrons in the given ion [tex]\( \,_{80}^{204}\text{Hg}^{2+} \)[/tex].

### 1. Number of Protons:
The atomic number (Z) represents the number of protons in the atom. For mercury (Hg), the atomic number is 80. Therefore, the number of protons ([tex]\( p^{+} \)[/tex]) is:
[tex]\[ 80 \, p^{+} \][/tex]

### 2. Number of Neutrons:
The mass number (A) of an atom is the sum of the number of protons and neutrons. For this mercury isotope, the mass number is 204. To find the number of neutrons ([tex]\( n^{0} \)[/tex]), we subtract the number of protons from the mass number:
[tex]\[ \text{Number of neutrons} = A - Z = 204 - 80 = 124 \, n^{0} \][/tex]

### 3. Number of Electrons:
In a neutral atom, the number of electrons equals the number of protons. However, the given ion is [tex]\( \text{Hg}^{2+} \)[/tex], meaning it has lost 2 electrons. Originally, the neutral mercury atom would have 80 electrons, so the Hg [tex]\(2+\)[/tex] ion has:
[tex]\[ \text{Number of electrons} = 80 - 2 = 78 \, e^{-} \][/tex]

### Conclusion:
Hence, the number of protons, neutrons, and electrons in the given ion [tex]\( \,_{80}^{204}\text{Hg}^{2+} \)[/tex] are:
- Protons: [tex]\( 80 \)[/tex]
- Neutrons: [tex]\( 124 \)[/tex]
- Electrons: [tex]\( 78 \)[/tex]

Thus, the correct choice is:
[tex]\[ 80 \, p^{+}, 124 \, n^{0}, 78 \, e \][/tex]