Historically the dining room is furnished with a rather large dining table and a number of dining chairs; the most common shape is generally rectangular with two armed end chairs and an even number of un-armed side chairs along the long sides.
Protons and neutrons do not have the same mass. Their masses are quite close, but they are noticeably different. For some purposes it is okay to equate the neutron and proton mass, but it's just an approximation.Also, neutrons decay into a proton, an electron and an antineutrino.rotons and neutrons do not have the same mass. Their masses are quite close, but they are noticeably different. For some purposes it is okay to equate the neutron and proton mass, but it's just an approximation.
1 Isotopes have the same atomic number (same number of protons), but a different atomic mass number (a different number of neutrons). 2  Isotopes behave the same chemically, because they are the same element. 3  The only difference is that one is heavier than the other, because of the additional neutrons.