Calculate the weighted average atomic mass for this unknown element with three isotopes: X-44 with a mass of 43.955 amu and a relative abundance of 2.1%, X-
40 with a mass of 39.963 amu and a relative abundance of 96.9%, X-42 with a
mass of 41.959 amu and a relative abundance of 0.7%. Identify the unknown
element based upon the weighted average atomic mass.