2.2 Chromium has four naturally-occurring isotopes: 4.34% of $^{50}Cr$, with an atomic weight of 49.9460 amu, 83.79% of $^{52}Cr$, with an atomic weight of 51.9405 amu, 9.50% of $^{53}Cr$, with an atomic weight of 52.9407 amu, and 2.37% of $^{54}Cr$, with an atomic weight of 53.9389 amu. On the basis of these data, confirm that the average atomic weight of Cr is 51.9963 amu.