An ion has 108 electrons, 108 protons, and 110 neutrons. What is the mass number of this ion?

• A. 216
• B. 110
• C. 218
• D. 108

Answer: (C)

Verified step by step guidance

1. Recall that the mass number (A) of an atom or ion is the total number of protons and neutrons in its nucleus.
2. Identify the number of protons given in the problem: 108 protons.
3. Identify the number of neutrons given in the problem: 110 neutrons.
4. Use the formula for mass number: \(A = \text{number of protons} + \text{number of neutrons}\).
5. Substitute the values: \(A = 108 + 110\) to find the mass number.