An element x has a dibrom ide with the empirical formula xbr2 and a dichloride with the empirical formula xci2. the dibromide is completely converted to the dichloride when it is heated in a stream of chlorine according to the reaction $$xbr2 + cl2 → xci2 + br2$$ when 1.500 g xbr2 is treated, 0.890 g xci2 results. (a) calculate the atomic mass of the element x. (b) by reference to a list of the atomic masses of the elements, identify the element x.