What is the total number of subatomic particles found in the nucleus of an atom of argon-40?

• A. 40
• B. 18
• C. 58
• D. 22

Answer: (A)

Verified step by step guidance

1. Identify the isotope given: argon-40. The number 40 represents the mass number (A), which is the total number of protons and neutrons in the nucleus.
2. Determine the atomic number (Z) of argon, which is the number of protons. Argon has an atomic number of 18, meaning it has 18 protons in its nucleus.
3. Calculate the number of neutrons (N) by subtracting the atomic number from the mass number: \(N = A - Z = 40 - 18\).
4. Find the total number of subatomic particles in the nucleus by adding the number of protons and neutrons: \(\text{Total} = Z + N\).
5. Sum the values from the previous steps to get the total number of subatomic particles in the nucleus of argon-40.