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.
Neutrons do not have a net electric charge, so the number of neutrons does not matter to the calculation. 1  The number of protons of an atom cannot change, so you add or subtract electrons to get the correct charge. If an ion has a 2+ charge, like Zn2+, this means there are two more protons than electrons.