How many protons are present in the nucleus of a single atom of 56 26 Fe?

• A. 82
• B. 26
• C. 56
• D. 30

Answer: (B)

Verified step by step guidance

1. Identify the notation of the element given: \(^{56}_{26} \mathrm{Fe}\). Here, the lower number (26) is the atomic number, and the upper number (56) is the mass number.
2. Recall that the atomic number represents the number of protons in the nucleus of an atom. This is a fundamental property of each element and defines the element itself.
3. Understand that the mass number (56) is the total number of protons and neutrons combined in the nucleus, but it does not affect the count of protons alone.
4. Therefore, to find the number of protons in the nucleus of this iron atom, simply use the atomic number, which is 26.
5. Conclude that the number of protons in a single atom of \(^{56}_{26} \mathrm{Fe}\) is 26.