A crystalline bromide of an unknown metallic element
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
A crystalline bromide of an unknown metallic element, denoted MBr2, is analyzed and found to contain 71.45% bromine by mass.
A student is asked to identify the element M and account for the stoichiometric relationship between the cation Mn+ and the bromide anion in the compound.
(a) Calculate the molar mass of the compound MBr2 using the reported mass percent of bromine.
(b) Determine the atomic mass of the element M to the appropriate number of significant figures.
(c) Using a standard periodic table, identify the element M.
(d) Justify how the charge on the cation Mn+ is consistent with both the empirical formula and the position of the element in the periodic table, referring explicitly to its valence-electron configuration.