Final answer:
Calcium carbonate is considered a compound because it is composed of two or more types of atoms chemically bonded together. The ratio of Ca : C : O atoms in the formula is 1 : 1 : 3. In the solid state, it exists as a solid compound, forming molecular crystals.
Step-by-step explanation:
Calcium carbonate (CaCO3) is considered a compound because it is composed of two or more types of atoms chemically bonded together. In this case, it is composed of calcium (Ca), carbon (C), and oxygen (O) atoms.
The ratio of Ca : C : O atoms in the formula is 1 : 1 : 3. This means that there is one calcium atom, one carbon atom, and three oxygen atoms in each molecule of calcium carbonate.
In the solid state, calcium carbonate exists as a solid compound. It forms molecular crystals because it is a covalently bonded compound.