The symbol for a radioactive nuclide is [tex][tex]${ }_{56}^{131} Ba$[/tex][/tex]. Which statement is correct?

A. The atomic number of the radioactive nuclide is 75.
B. The mass number of the radioactive nuclide is 131.
C. The number of neutrons that are present in the nucleus of each atom is 56.
D. The number of protons that are present in the nucleus of each atom is 131.



Answer :

To determine which of the provided statements about the radioactive nuclide [tex]\(\ce{_{56}^{131}Ba}\)[/tex] is correct, we can analyze each statement based on the properties of the nuclide. Here's the step-by-step analysis:

1. Atomic Number and Mass Number:
- The symbol [tex]\(\ce{_{56}^{131}Ba}\)[/tex] tells us that the atomic number ([tex]\(Z\)[/tex]) is 56. This number indicates the number of protons in the nucleus.
- The mass number ([tex]\(A\)[/tex]) is 131. This number is the sum of protons and neutrons in the nucleus.

2. Calculating the Number of Neutrons:
- The number of neutrons ([tex]\(N\)[/tex]) in the nucleus can be calculated using the formula:
[tex]\[ N = A - Z \][/tex]
Substituting the known values:
[tex]\[ N = 131 - 56 = 75 \][/tex]
Therefore, there are 75 neutrons in the nucleus of [tex]\(\ce{_{56}^{131}Ba}\)[/tex].

3. Evaluating Each Statement:
- Statement 1: The atomic number of the radioactive nuclide is 75.
[tex]\[ \text{This statement is false because the atomic number is 56, not 75.} \][/tex]

- Statement 2: The mass number of the radioactive nuclide is 131.
[tex]\[ \text{This statement is true because the mass number is indeed 131.} \][/tex]

- Statement 3: The number of neutrons that are present in the nucleus of each atom is 56.
[tex]\[ \text{This statement is false because the number of neutrons is 75, not 56.} \][/tex]

- Statement 4: The number of protons that are present in the nucleus of each atom is 131.
[tex]\[ \text{This statement is false because the number of protons is 56, not 131.} \][/tex]

After evaluating all statements, we conclude that:
- The only correct statement is: The mass number of the radioactive nuclide is 131.

Thus, among the provided statements, Statement 2 is the correct one.