Multiple choice general knowledge science & technology

If a fluorine atom has 10 neutrons and 9 protons, its atomic number is?

  1. 19

  2. 90

  3. 18

  4. 9

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The atomic number of an element equals the number of protons in its nucleus. Fluorine has 9 protons, so its atomic number is 9. The number of neutrons (10) is irrelevant to determining atomic number, and 19 (total nucleons) would be the mass number, not atomic number. 90 has no relation to fluorine's properties.