Oxygen has an atomic number of 8. What can you conclude from this fact?

• A. An oxygen atom contains 8 neutrons in its nucleus.
• B. An oxygen atom contains 8 electrons in its nucleus.
• C. An oxygen atom contains 8 protons in its nucleus.
• D. Oxygen has a mass number of 8.

Answer: (C)

Verified step by step guidance

1. Understand that the atomic number of an element represents the number of protons in the nucleus of an atom of that element.
2. Recall that the atomic number does not directly tell you the number of neutrons or electrons; it specifically indicates the number of protons.
3. Recognize that for a neutral atom, the number of electrons equals the number of protons, but electrons are not located in the nucleus.
4. Note that the mass number is the sum of protons and neutrons, and it is different from the atomic number; the problem states oxygen has an atomic number of 8, not a mass number of 8.
5. Conclude that since oxygen's atomic number is 8, an oxygen atom contains exactly 8 protons in its nucleus.