Khối lượng nguyên tử Al:
\(m_{Al}=13u+14u=27u=27\cdot1,6605\cdot10^{-27}=4,48\cdot10^{-26}\left(kg\right)\)
Khoi luong nguyen tu nhom m=mp+me+mn
voi
m 1 proton = 1.67*10^-27 => m 13proton = 21.71*10^-27 (kg)
m1e=9.1*10^-31 => m13e = 118.3*10^-31 (kg)
m1n = 1.67*10^-27=>m13n=21.71*10^-27(kg)