An atom of krypton-84 (Kr) has an atomic number of 36. How many neutrons are present in one atom of krypton-84?

• A. 84
• B. 48
• C. 52
• D. 36

Answer: (B)

Verified step by step guidance

1. Identify the atomic number of krypton (Kr), which is given as 36. The atomic number represents the number of protons in the nucleus of the atom.
2. Recognize that the number 84 in krypton-84 is the mass number, which is the total number of protons and neutrons in the nucleus.
3. Use the relationship between mass number (A), number of protons (Z), and number of neutrons (N): \(A = Z + N\).
4. Rearrange the formula to solve for the number of neutrons: \(N = A - Z\).
5. Substitute the known values into the equation: \(N = 84 - 36\), which will give the number of neutrons in krypton-84.