An isotope of the element fluorine has 9 protons and 10 neutrons. What is the name of this isotope?

• A. Fluorine-19
• B. Fluorine-18
• C. Fluorine-9
• D. Fluorine-10

Answer: (A)

Verified step by step guidance

1. Identify the number of protons in the isotope. Since the element is fluorine, it has 9 protons, which defines the element's identity.
2. Determine the number of neutrons given in the problem, which is 10 neutrons for this isotope.
3. Calculate the mass number (A) of the isotope by adding the number of protons (Z) and neutrons (N): \(A = Z + N\).
4. Substitute the values: \(A = 9 + 10\) to find the mass number of the isotope.
5. Name the isotope by combining the element name with the mass number, resulting in the format 'Element-MassNumber', for example, 'Fluorine-19'.