# What is the isotopic distribution of the chromium atom?

""^(50)Cr, 4.3%; ""^(52)Cr, 83.8%; ""^(53)Cr, 9.5%; ""^(54)Cr, 2.4%. This is the natural isotopic distribution of the transition metal. The weighted average of the isotopes, is the atomic mass we would use for chromium when we calculate an atomic mass for the metal, i.e. $C r , 51.997 \cdot g \cdot m o {l}^{-} 1$, and this mass is necessarily close to the MOST common isotope, i.e. ""^52Cr.