1 a.m.u is defined as the 1/12th mass of a atom of carbon-12 .Is the carbon-12 and the carbon (in the periodic table) the same.

An atomic mass unit or amu is defined as one twelfth of the mass of an unbound atom of carbon -12. It is a unit of mass, used to express atomic masses and molecular masses.By definition, 12 amu equals the atomic mass of carbon-12.Although carbon exist in different isotopic forms ,but in this reference scale of a.m.u ,C-12 refers to carbon which has atomic number 6 in the periodic table having 6 protons and 6 neutrons respectively.

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