Final answer:
To find the number of neutrons in an atom, subtract the atomic number from the mass number. Both ⁵⁷Co and ⁵⁸Ni have 30 neutrons, but since ⁵⁸Ni is identical to the reference isotope, the correct answer is A) ⁵⁷Co.
Step-by-step explanation:
The student is asking which of the listed atoms has the same number of neutrons as ⁵⁸Ni. To find the number of neutrons in an atom, you subtract the atomic number (number of protons) from the mass number. The mass number of nickel-58 (⁵⁸Ni) is 58 and the atomic number of nickel is 28 (since it has 28 protons), so it has 58 - 28 = 30 neutrons.
We perform this calculation for each of the given options:
- ⁵⁷Co: Mass number = 57, atomic number (protons) = 27, neutrons = 57 - 27 = 30
- ⁵⁸Fe: Mass number = 58, atomic number (protons) = 26, neutrons = 58 - 26 = 32
- ⁵⁸Ni: Mass number = 58, atomic number (protons) = 28, neutrons = 58 - 28 = 30
- ⁵⁹Co: Mass number = 59, atomic number (protons) = 27, neutrons = 59 - 27 = 32
- ⁶⁰Cu: Mass number = 60, atomic number (protons) = 29, neutrons = 60 - 29 = 31
Based on these calculations, options A) ⁵⁷Co and C) ⁵⁸Ni both have the same number of neutrons as ⁵⁸Ni, which is 30. However, since ⁵⁸Ni is essentially the same isotope being compared to itself, the correct answer is A) ⁵⁷Co.