Subatomic particles in hydrogen species

Steps:

• Identify O as proton (relative mass 1, charge +1) and • as electron (relative mass ~0, charge -1) from typical diagrams.
• Recall hydrogen atom (H) has one proton and one electron for neutrality.
• Note hydrogen ion (H+) forms by losing the electron, leaving only the proton.
• Match to choices: both particles in H, only proton (O) in H+.

Why C is correct:

• Hydrogen ion (H+) is defined as a proton (H nucleus), excluding the electron per atomic structure.

Why the others are wrong:

• A: Incorrectly includes electron in H+, which is not present.
• B: Fails to specify particles in H+; implies neither, but proton exists.
• D: Reverses particles, placing electron in H+ and excluding proton from H.

Final answer: C