Concept Explanation: Mass of a Proton

A proton is a subatomic particle found in the nucleus of an atom. It has a positive charge and a specific mass. To determine what has the same mass as a proton, we need to compare it with the given options.

Step 1: Understand the Mass of a Proton

The mass of a proton is approximately $1.67 \times 10^{- 27} kg$ . This is often used as a standard unit in atomic mass units (u), where 1 u = mass of a proton ≈ $1.67 \times 10^{- 27} kg$ .

Step 2: Compare with Options

Hydrogen ion: A hydrogen ion (H⁺) is essentially a proton since hydrogen atom loses its electron. Thus, its mass is the same as a proton.
An electron: An electron has a much smaller mass, about $9.11 \times 10^{- 31} kg$ , which is roughly 1/1836 times the mass of a proton.
Oxygen atom: An oxygen atom has a mass of about 16 u (atomic mass unit), which is 16 times the mass of a proton.
Carbon atom: A carbon atom has a mass of about 12 u, which is 12 times the mass of a proton.

Step 3: Conclusion

Only the hydrogen ion has the same mass as a proton because it is essentially a proton itself after losing its electron.

Final Answer

The mass of a proton is the same as that of a hydrogen ion.

Related Topics and Formulae

Atomic Mass Unit (u): It is defined as one-twelfth the mass of a carbon-12 atom. 1 u = $1.660539 \times 10^{- 27} kg$ , which is approximately the mass of a proton or neutron.

Proton and Hydrogen Ion: A hydrogen atom consists of one proton and one electron. When it loses its electron, it becomes a hydrogen ion (H⁺), which is just a proton. Hence, their masses are identical.

Mass Comparison: $Mass of proton \approx Mass of hydrogen ion >> Mass of electron$