An atom of fluorine has an atomic number of 9 and a mass number of 19. Which of the following statements is correct?
A) An atom of fluorine has 9 protons, 9 electrons, and 10 neutrons.
B) An atom of fluorine has 9 protons, 9 electrons, and 9 neutrons.
C) An atom of fluorine has 9 protons, 10 electrons, and 9 neutrons.
D) An atom of fluorine has 10 protons, 9 electrons, and 9 neutrons.
E) An atom of fluorine has 9 protons, 9 electrons, and 19 neutrons.

Question

Quizplus · Accepted Answer

An atom of fluorine has an atomic number of 9, meaning it has 9 protons and, in a neutral atom, 9 electrons. The mass number is 19, which is the sum of protons and neutrons, so it has 10 neutrons (19 - 9 = 10).

An Atom of Fluorine Has an Atomic Number of 9