Answer
manganese (II) oxide
Work Step by Step
The element with chemical symbol Mn is manganese, according to the periodic table; the element with chemical symbol O is oxygen. Manganese has more than one oxidation state. Oxygen has a common oxidation state of 2- because it readily accepts two electrons. Therefore, in this compound, manganese must have an oxidation of 2+ in order to balance the 2- oxidation state of oxygen. Manganese takes on a 2+ charge by donating two electrons to the oxygen atom whereas oxygen accepts the two electrons and becomes an anion with a 2- charge.
The chemical formula MnO stands for manganese oxide, but we must, according to the modern system for writing the names of ionic compounds, specify the oxidation state of manganese by inserting a Roman numeral after "manganese" to reflect its oxidation state of 2+. Therefore, this compound's name, according to the modern system, is manganese (II) oxide.