Which element has 13 protons in its nucleus?

• A. Silicon (Si)
• B. Magnesium (Mg)
• C. Phosphorus (P)
• D. Aluminum (Al)

Answer: (D)

Verified step by step guidance

1. Recall that the number of protons in the nucleus of an atom defines the atomic number of the element.
2. Identify the atomic numbers of the given elements: Silicon (Si) has 14 protons, Magnesium (Mg) has 12 protons, Phosphorus (P) has 15 protons.
3. Understand that the element with 13 protons corresponds to the atomic number 13.
4. Look up the periodic table to find the element with atomic number 13, which is Aluminum (Al).
5. Conclude that Aluminum (Al) is the element with 13 protons in its nucleus.