Which of the following statements about magnesium is correct?

• A. Magnesium has 8 protons in its nucleus.
• B. Magnesium is a transition metal.
• C. Magnesium has an atomic number of 12.
• D. Magnesium is a noble gas.

Answer: (C)

Verified step by step guidance

1. Recall that the atomic number of an element is equal to the number of protons in its nucleus. This number uniquely identifies the element.
2. Check the atomic number of magnesium on the periodic table. Magnesium has an atomic number of 12, meaning it has 12 protons in its nucleus.
3. Understand that magnesium is an alkaline earth metal, located in group 2 of the periodic table, not a transition metal (which are found in groups 3-12).
4. Recognize that magnesium is not a noble gas; noble gases are found in group 18 and are characterized by their inertness and full valence electron shells.
5. Therefore, the correct statement is that magnesium has an atomic number of 12, which corresponds to having 12 protons in its nucleus.