Question

an atom of fluorine has the atomic number 9, and its mass number is 19. which of the following shows a neutral atom of fluorine? w. x. y. z. a. z b. y c. x

Explanation:

Step1: Recall atomic - number and mass - number concepts

The atomic number of an element is the number of protons. For fluorine, atomic number = 9, so number of protons = 9. In a neutral atom, the number of electrons is equal to the number of protons. So, a neutral fluorine atom has 9 electrons. The mass number is the sum of protons and neutrons. Given mass number = 19 and number of protons = 9, the number of neutrons = mass number - number of protons = 19 - 9=10.

Answer:

We need to find the option that shows 9 protons, 9 electrons and 10 neutrons. Since the options are not shown in full, we assume that the correct option is the one that has these correct particle - numbers. Without the full content of W, X, Y, Z, we cannot give a definite letter - based answer. But conceptually, the correct atom model should have 9 protons, 9 electrons and 10 neutrons.