Video Transcript
Which element does an oxide, a compound containing two elements, contain at least one atom of?
The question asks about an oxide. We can define an oxide as a chemical compound that contains at least one oxygen atom chemically bonded to an atom of another element. We know that a compound consists of two or more different elements chemically joined together. And we are specifically told in the question that an oxide compound has only two different elements joined together. Our definition of an oxide tells us a bit more about the two different elements. One of the elements is oxygen, chemical symbol O. And for the second, we are just told another element. Let’s call it X. X can be a metal, for example, calcium, sodium, iron, or lithium. Or X can be a nonmetal, for example, carbon, sulfur, or nitrogen. X can be a metalloid, and an example is silicon.
The subscripts a and b will vary depending on the oxide compound and according to the element to which the oxygen atom or atoms are bonded. For example, for the metals shown, the formulas are CaO, or calcium oxide, Na2O for sodium oxide, Fe2O3 for iron(III) oxide, and Li2O for lithium oxide. When X is a nonmetal, we get, for example, CO, or carbon monoxide. Another example is SO3, sulfur trioxide. And an example of a nitrogen oxide is dinitrogen tetroxide, N2O4. If oxygen is bonded to a metalloid such as silicon, we might get silicon dioxide, SiO2.
We have seen that in the case of metal oxides or nonmetal oxides or even metalloid oxide compounds, there is only one element bonded to oxygen. So oxides are binary compounds, where bi- refers to two, in this case two elements. We have also confirmed by looking at several formulas that there is at least one oxygen atom in an oxide formula.
Finally, which elements does an oxide, a compound containing two elements, contain at least one atom of? The answer is oxygen.
