Which numbers are typically shown in the symbol for a radioactive nuclide?

• A. The mass number and the number of electrons
• B. The mass number and the atomic number
• C. The number of protons and the number of neutrons
• D. The atomic number and the number of neutrons

Answer: (B)

Verified step by step guidance

1. Understand that a radioactive nuclide symbol typically includes two key numbers: the mass number and the atomic number.
2. Recall that the mass number (A) represents the total number of protons and neutrons in the nucleus of the atom.
3. Recognize that the atomic number (Z) represents the number of protons in the nucleus, which defines the element.
4. Note that the number of electrons is not usually shown in the nuclide symbol because it can vary in ions, and the number of neutrons is not directly shown but can be found by subtracting the atomic number from the mass number: \(\text{Number of neutrons} = A - Z\).
5. Therefore, the standard notation for a nuclide is written as \(^{A}_{Z}X\), where \(X\) is the chemical symbol, \(A\) is the mass number, and \(Z\) is the atomic number.