A radioactive nuclide has 53 protons and 78 neutrons. Which is the symbol of this nuclide?

• A. Te-131
• B. I-131
• C. I-78
• D. Xe-131

Answer: (B)

Verified step by step guidance

1. Identify the element by the number of protons. The number of protons (atomic number) determines the element's identity. Here, the nuclide has 53 protons.
2. Use the periodic table to find the element with atomic number 53. This element is Iodine (I).
3. Calculate the mass number (A) by adding the number of protons and neutrons: \(A = Z + N = 53 + 78\).
4. Write the nuclide symbol in the form \(^{A}_{Z}X\), where \(X\) is the element symbol, \(A\) is the mass number, and \(Z\) is the atomic number. For this nuclide, it will be \(^{131}_{53}I\).
5. Express the nuclide symbol in the common shorthand notation as Element-Mass Number, which is I-131.