A = Z + N
Si = 14 + 28 = A x m(nucléon) = 42 x 1,67 x 10⁻²⁷ = 7,0 x 10⁻²⁶ kg
W = 74 + 183 = 257 x 1,67 x 10⁻²⁷ = 4,11 x 10⁻²⁵ kg
Ca = 20 + 40 = 60 x 1,67 x 10⁻²⁷ = 1,0 x 10⁻²⁵ kg
I = 53 + 126 = 179 x 1,67 x 10⁻²⁷ = 2,98 x 10⁻²⁵ kg
Kr = 36 + 83 = 119 x 1,67 x 10⁻²⁷ = 1,98 x 10⁻²⁵ kg
Fr = 57 + 223 = 310 x 1,67 x 10⁻²⁷ = 5,17 x 10⁻²⁵ kg
