Silver has an atomic number of 47.
a. Give the number of protons, neutrons, and electrons in a neutral atom of the most common isotope, Ag-107.
b. How do the numbers of protons, neutrons, and electrons in a neutral atom of Ag-109 compare with those of Ag-107?
The correct answer and explanation is :
a. Number of Protons, Neutrons, and Electrons in Ag-107
Silver (Ag) has an atomic number of 47, which means that in a neutral atom of silver, there are 47 protons and 47 electrons. The atomic number is always equal to the number of protons in an element, and for a neutral atom, the number of electrons equals the number of protons.
For the most common isotope of silver, Ag-107, the “107” represents the atomic mass, which is the sum of protons and neutrons in the nucleus. The number of neutrons can be found by subtracting the atomic number (47 protons) from the atomic mass number (107):
[
\text{Neutrons} = \text{Atomic Mass} – \text{Number of Protons} = 107 – 47 = 60
]
Thus, for the isotope Ag-107:
- Protons = 47
- Neutrons = 60
- Electrons = 47 (since it is neutral)
b. Comparison Between Ag-109 and Ag-107
Ag-109 is another isotope of silver, with an atomic mass number of 109. Just like Ag-107, silver’s atomic number remains 47. Therefore, both Ag-107 and Ag-109 have the same number of protons and electrons. In a neutral atom, the number of protons is equal to the number of electrons, so:
- Protons in Ag-109 = 47
- Electrons in Ag-109 = 47
However, the main difference between Ag-107 and Ag-109 lies in the number of neutrons. To find the number of neutrons in Ag-109, we subtract the atomic number (47 protons) from the atomic mass (109):
[
\text{Neutrons in Ag-109} = 109 – 47 = 62
]
So, for Ag-109:
- Protons = 47
- Neutrons = 62
- Electrons = 47
Summary of Differences:
- The number of protons in both isotopes is the same (47), as it is determined by the atomic number.
- The number of neutrons differs between the isotopes: Ag-107 has 60 neutrons, while Ag-109 has 62 neutrons.
- The number of electrons in both isotopes is the same (47), assuming both are neutral atoms.
The difference in the number of neutrons results in different atomic masses (107 for Ag-107 and 109 for Ag-109), but both isotopes are chemically the same because they have the same number of protons and electrons.