Which element has 13 protons in its nucleus?

• A. Silicon
• B. Magnesium
• C. Sodium
• D. Aluminum

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, Sodium (Na) has 11 protons, and Aluminum (Al) has 13 protons.
3. Match the atomic number 13 to the corresponding element, which is Aluminum.
4. Understand that the atomic number uniquely identifies an element, so any atom with 13 protons is aluminum regardless of its isotope or ionization state.
5. Therefore, the element with 13 protons in its nucleus is Aluminum.