Atomic and molecolar structure

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Exercises in nuclear reactor physics by ing. Giorgio Bertucelli.

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The Atomic mass unit (amu) is the 12^th part of the mass of C₆¹² atom.
Thus the mass of C₆¹² atom = 12 amu

• Neutron mass =1,00897 amu
• Proton mass =1,00758 amu
• Electron mass =0,00055 amu
• Mass of hydrogen atom =1,00758amu + 0,00055 amu = 1.00813 amu

One mole of atoms of every element is the quantity of substance containing exactly the same number of atoms of 12 g of pure C₆¹².
This number is the N_A = 6,0221415 ·10²³ (according to CODATA of 2002)

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