How many atoms of each element are in a formula unit of calcium carbonate, CaCO3?
a. 3 calcium atoms, 2 carbon atoms, 8 oxygen atoms
b. 2 calcium atoms, 3 carbon atoms, 12 oxygen atoms
c. 1 calcium atom, 1 carbon atom, 3 oxygen atoms
d. 2 calcium atoms, 1 carbon atom, 4 oxygen atoms
e. 1 calcium atom, 1 carbon atom, 4 oxygen atoms
The Correct Answer and Explanation is :
The correct answer is:
c. 1 calcium atom, 1 carbon atom, 3 oxygen atoms
Explanation:
Calcium carbonate (CaCO₃) is a chemical compound made up of three different elements: calcium (Ca), carbon (C), and oxygen (O). The chemical formula tells us the number of each type of atom present in one formula unit of the compound.
Breaking down the formula:
- Ca (Calcium)
- The formula shows “Ca,” meaning there is one calcium atom per formula unit.
- C (Carbon)
- The formula has “C,” which indicates that there is one carbon atom.
- O (Oxygen)
- The subscript “₃” next to oxygen (O) means that there are three oxygen atoms.
Why is option C correct?
- The formula CaCO₃ explicitly states that one molecule of calcium carbonate contains:
- 1 calcium atom
- 1 carbon atom
- 3 oxygen atoms
Why are the other options incorrect?
- Option A (3 Ca, 2 C, 8 O): Incorrect because the formula does not indicate multiple calcium or carbon atoms.
- Option B (2 Ca, 3 C, 12 O): Incorrect because the correct formula does not support these numbers.
- Option D (2 Ca, 1 C, 4 O): Incorrect because CaCO₃ has only one calcium atom.
- Option E (1 Ca, 1 C, 4 O): Incorrect because there are only three oxygen atoms, not four.
Thus, the correct answer is C (1 Ca, 1 C, 3 O).
Now, I’ll generate an image representing calcium carbonate at the atomic level.
Here is an image representing the molecular structure of calcium carbonate (CaCO₃), showing the individual atoms and their bonding. Let me know if you need any modifications or additional explanations!