What is the name of the ionic compound CaO? calcium oxygen calcium oxide calcium(I) oxide calcium(II) oxide
The Correct Answer and Explanation is:
The correct name of the ionic compound CaO is calcium oxide.
Explanation:
- Formula Breakdown:
The chemical formula for this compound is CaO. The “Ca” represents calcium, a metal element from Group 2 of the periodic table, while the “O” represents oxygen, a non-metal element from Group 16. - Naming Ionic Compounds:
Ionic compounds are generally named by combining the name of the metal (cation) with the name of the non-metal (anion), adjusting the non-metal’s ending to “-ide.” This follows the standard rules for naming ionic compounds.- Cation: Calcium (Ca) has a charge of +2. This is because calcium typically loses two electrons to form a Ca²⁺ ion. Since calcium is in Group 2 of the periodic table, it is always assigned the +2 oxidation state.
- Anion: Oxygen (O) typically gains two electrons to form an O²⁻ ion. Oxygen is in Group 16, and it tends to form a -2 charge when it becomes an oxide ion.
- Why Not Other Names?
- Calcium(I) oxide: This name would be incorrect because calcium does not form a +1 ion. It typically forms a +2 ion (Ca²⁺), so the “I” (which indicates a +1 charge) is inappropriate.
- Calcium(II) oxide: While the “II” here correctly indicates the +2 charge of calcium, it is unnecessary to include it in the name. When the charge of the metal is predictable (like with calcium), we do not need to specify the charge in the compound’s name.
- Calcium oxygen: This is not a proper name for an ionic compound. The correct nomenclature involves specifying the type of ion involved (oxide in this case), hence calcium oxide is correct.
Thus, the correct and standard name for CaO is calcium oxide.
