How many protons are in an atom of magnesium (Mg)?

• A. 12
• B. 10
• C. 14
• D. 24

Answer: (A)

Verified step by step guidance

1. Identify the element in question, which is magnesium (Mg). Each element is defined by its atomic number.
2. Recall that the atomic number of an element represents the number of protons in the nucleus of an atom of that element.
3. Look up the atomic number of magnesium on the periodic table. Magnesium has an atomic number of 12.
4. Therefore, the number of protons in an atom of magnesium is equal to its atomic number, which is 12.
5. Confirm that the number of protons is not confused with the atomic mass or number of neutrons; only the atomic number gives the proton count.