An Fe^{2+} ion has a mass number of 56. How many neutrons are present in a single Fe^{2+} atom?

• A. 28
• B. 30
• C. 32
• D. 26

Answer: (B)

Verified step by step guidance

1. Identify the mass number (A) of the Fe^{2+} ion, which is given as 56. The mass number represents the total number of protons and neutrons in the nucleus.
2. Determine the atomic number (Z) of iron (Fe), which is the number of protons. For iron, Z = 26.
3. Recall that the number of neutrons (N) can be found using the formula: \(N = A - Z\).
4. Substitute the known values into the formula: \(N = 56 - 26\).
5. Calculate the difference to find the number of neutrons in the Fe^{2+} ion.