Question

1. the error made on compound iv is that: a. a roman numeral should be used to represent magnesiums charge b. it is an ionic compound and therefore should have a \mono\ included with magnesium c. swapping and dropping the charges was done incorrectly d. it is an ionic compound and therefore prefixes should not be used

Explanation:

Magnesium is a Group - 2 element with a fixed charge of + 2 and does not require Roman numerals to indicate its charge. Roman numerals are used for transition metals with variable charges. Also, prefixes like "mono -" are used for naming covalent compounds, not ionic compounds. In naming ionic compounds, we swap the charges and drop the signs to get the correct formula. In the case of magnesium compounds, since it has a fixed + 2 charge, using a Roman numeral IV to represent its charge is incorrect.

Answer:

a. A roman numeral should be used to represent Magnesium's charge is the error made on compound IV.