Which element has 25 protons in its nucleus?

• A. Cobalt (Co)
• B. Manganese (Mn)
• C. Iron (Fe)
• D. Chromium (Cr)

Answer: (B)

Verified step by step guidance

1. Recall that the number of protons in the nucleus of an atom defines the element and is called the atomic number.
2. Look up the atomic numbers of the given elements: Cobalt (Co), Manganese (Mn), Iron (Fe), and Chromium (Cr).
3. Identify the element whose atomic number is 25, since the problem states the element has 25 protons.
4. Remember that the atomic number corresponds directly to the number of protons, so the element with atomic number 25 is the one with 25 protons.
5. Confirm that Manganese (Mn) has the atomic number 25, making it the correct answer.