Final answer:
The multivalent ionic compound among the given choices is CuO, which is named copper(II) oxide, indicating that copper has a +2 charge.
Step-by-step explanation:
To find the multivalent ionic compound(s) and name their charge among CaC2O4, CH3CH2CH3, CuO, CdCO3, you should look for compounds containing metals that can exhibit more than one ionic charge. The compound CH3CH2CH3 (propane) is an organic molecule and not ionic. The compounds CaC2O4 (calcium oxalate) and CdCO3 (cadmium carbonate) contain metals with a single common ionic charge of +2, thus not multivalent. The compound of concern here is CuO, where copper is the metal that can have multiple charges.
In the case of CuO, oxygen always has a charge of -2. Since there is only one oxygen atom, copper must have a charge of +2 to balance the charges. Therefore, the proper name of this multivalent ionic compound is copper(II) oxide. This follows the naming convention for ionic compounds where the metal cation's charge is indicated in roman numerals within parentheses right after the metal's name, if the metal can have more than one charge.