Here's why:
* Atomic Mass Unit (amu): This unit is defined as 1/12th the mass of a carbon-12 atom.
* Proton and Neutron Mass: Protons and neutrons are the main components of an atom's nucleus. They have very similar masses, with protons being slightly heavier.
* Approximation: For many calculations, it's convenient to approximate the mass of a proton (and neutron) as 1 amu.
It's important to note that the actual mass of a proton is slightly more than 1 amu:
* Proton Mass: 1.007276466879 amu
However, for most general purposes, the approximation of 1 amu is sufficient.
