Which of the following elements has 30 neutrons in its most common isotope?

• A. Zinc (Zn)
• B. Palladium (Pd)
• C. Nickel (Ni)
• D. Copper (Cu)

Answer: (C)

Verified step by step guidance

1. Identify the atomic number of each element, which represents the number of protons in the nucleus. For Nickel (Ni), the atomic number is 28.
2. Determine the mass number of the most common isotope of Nickel. The mass number is the sum of protons and neutrons in the nucleus.
3. Use the formula: \( \text{Mass Number} = \text{Number of Protons} + \text{Number of Neutrons} \).
4. Substitute the known values into the formula: \( \text{Mass Number} = 28 + 30 \).
5. Verify that the calculated mass number corresponds to the most common isotope of Nickel, which is Nickel-58.