A metal X forms two chlorides with the formulae XCI2 and XCI3. Where is X in the Periodic Table?

Metal X forms two chlorides with formulae XCI₂ and XCI₃. The Roman numeral in the name of a metal chloride indicates the charge of the metal ion. The chlorine atom has a fixed charge of -1. Since the formula of XCI₂ has two chlorine atoms, the total charge contributed by the chlorine atoms is -2. Therefore, the charge of the metal ion in XCI₂ must be +2 in order for the compound to be electrically neutral. Likewise, the charge of the metal ion in XCI₃ must be +3 in order for the compound to be electrically neutral. From the above information, we can conclude that the metal X has variable oxidation states of +2 and +3. This means that the metal X must be a transition metal and located in the d-block of the periodic table. Therefore, the correct answer is "d-block."