Hydrogen and carbon have significantly different masses due to their atomic structures and the number of particles they contain. The mass of an atom is primarily determined by the combined mass of its protons and neutrons, which are located in the nucleus, while the electrons surrounding the nucleus contribute very little to the overall mass of an atom.
In the case of hydrogen, the most common isotope is hydrogen-1 (denoted as ^1H). Hydrogen-1 consists of a single proton and no neutrons. The mass of a proton is approximately 1 atomic mass unit (u), so hydrogen-1 has a mass of approximately 1 u.
On the other hand, carbon-12 (denoted as ^12C) is the most abundant and stable isotope of carbon. It contains 6 protons and 6 neutrons in its nucleus, giving it a total mass of approximately 12 u.
Therefore, when comparing the mass of hydrogen-1 to carbon-12, hydrogen is approximately 8% as massive. This is because hydrogen-1 has only one proton, while carbon-12 has six protons and six neutrons. The additional protons and neutrons in carbon-12 contribute to its higher mass compared to hydrogen-1.