* Protons: The number of protons defines the element. Oxygen always has 8 protons.
* Neutrons: The number after the element's name (in this case, "17") is the mass number. The mass number represents the total number of protons and neutrons.
* To find the number of neutrons, subtract the number of protons from the mass number: 17 - 8 = 9 neutrons.
Therefore, oxygen-17 has 8 protons and 9 neutrons.
