Which of the following is not a correct formula unit? K 2 O MgO 2 Al 2 O 3 SrO

Hey everyone were asked to choose the compound with an incorrect name. Starting with the first one, we have M G O. Which is magnesium oxide. Now this one is going to be correct. So it can't be our answer. Magnesium oxide is an ionic compound and when we name ionic compounds, the metal keeps its name and it is written first and the nonmetal keeps its base name but its ending is changed to I. D. E. Which is exactly what we see here. For B we have F E C L two which is stated to be iron di chloride. Now this name is going to be incorrect and the reason why is because we know that chlorine has that minus one charge. So iron should have a plus two charge in order to end up with F E C L two. And as we've learned transition metals will have a roman numeral in order to denote its charge. So the name should actually be iron two chloride. But let's go ahead and continue looking at our answer choices. So for C we have tetra phosphorous hex oxide and this one is going to be correct because we have two non metals here. And since we have four phosphorus we add that prefix of tetra and for oxygen since we have six of oxygen we add the prefix of hex and we change the ending into I. D. So this one is going to be correct as well and it is a covalin compound. Now looking at our last one, we have M N. 02 which is said to be manganese for oxide. And this one is also correct, manganese is a transition metal. So that is why we have that roman numeral four in order to denote its plus four charge. And again we have the ending of I. D. For our non metal. And this is going to be an ionic compound as well. So our final answer here is going to be be Now. I hope that made sense and let us know if you have any questions.