How many protons are in a neutral potassium atom (K)?

• A. 18
• B. 39
• C. 20
• D. 19

Answer: (D)

Verified step by step guidance

1. Recall that the number of protons in an atom is equal to its atomic number, which uniquely identifies the element.
2. Identify the element given in the problem, which is potassium (K).
3. Look up the atomic number of potassium on the periodic table; this number represents the number of protons in a neutral potassium atom.
4. Understand that the atomic mass (such as 39) represents the total number of protons and neutrons, not just protons.
5. Conclude that the number of protons in a neutral potassium atom is equal to its atomic number, which is 19.