In which of the following is the number of neutrons correctly represented for the given isotope?

• A. Nitrogen-15: 8 neutrons
• B. Chlorine-35: 20 neutrons
• C. Oxygen-18: 10 neutrons
• D. Carbon-14: 8 neutrons

Answer: (A)

Verified step by step guidance

1. Recall that the number of neutrons in an isotope is calculated by subtracting the atomic number (number of protons) from the mass number (total number of protons and neutrons). The formula is: \(\text{Number of neutrons} = \text{Mass number} - \text{Atomic number}\).
2. Identify the atomic number for each element from the periodic table: Nitrogen (7), Chlorine (17), Oxygen (8), and Carbon (6).
3. Calculate the number of neutrons for each isotope by subtracting the atomic number from the given mass number. For example, for Nitrogen-15: \$15 - 7 = 8$ neutrons.
4. Repeat the calculation for Chlorine-35: \$35 - 17 = 18\( neutrons; Oxygen-18: \)18 - 8 = 10\( neutrons; Carbon-14: \)14 - 6 = 8$ neutrons.
5. Compare your calculated neutron numbers with the given values to determine which isotopes have the correct neutron count.