How many unshared electrons are found in the lewis dot structure of Carbon Dioxide or CO2?
The Correct Answer and Explanation is:
In the Lewis dot structure of Carbon Dioxide (CO2), there are 4 unshared electrons. Here’s how we determine this:
Step 1: Count the total number of valence electrons
Carbon (C) has 4 valence electrons (group 14 of the periodic table), and oxygen (O) has 6 valence electrons (group 16). Since there are 2 oxygen atoms, we can calculate the total number of valence electrons in CO2:(4 from carbon)+(2×6 from oxygen)=16 valence electrons(4 \, \text{from carbon}) + (2 \times 6 \, \text{from oxygen}) = 16 \, \text{valence electrons}(4from carbon)+(2×6from oxygen)=16valence electrons
Step 2: Draw the skeletal structure
Carbon is the central atom because it is less electronegative than oxygen. Oxygen atoms are bonded to the carbon atom. This gives a basic skeletal structure:O−C−OO – C – OO−C−O
Step 3: Distribute electrons to satisfy the octet rule
To satisfy the octet rule for each atom, carbon needs 8 electrons (4 bonds), and each oxygen atom needs 8 electrons. We place two electrons between each C-O bond (a single bond has 2 electrons).
Thus, we have:O:C:OO : C : OO:C:O
Step 4: Add lone pairs to complete octets
After the bonding electrons (4 electrons for the 2 bonds), we add lone pairs of electrons to the oxygen atoms. Each oxygen requires 6 more electrons to complete its octet. So, each oxygen atom gets 3 lone pairs of electrons (6 electrons) to complete its octet.
Step 5: Check carbon’s octet
Carbon, being in the center, shares 4 electrons with each oxygen atom (2 electrons per C-O bond). Carbon now has 8 electrons in total (4 from bonding). Therefore, it satisfies the octet rule.
Step 6: Counting unshared (lone) electrons
Now, for the unshared electrons:
- Each oxygen has 6 valence electrons, 2 of which are used in bonding with carbon. The remaining 4 electrons (2 lone pairs) are unshared for each oxygen atom. Therefore, each oxygen has 4 unshared electrons.
- Since there are 2 oxygen atoms, we have 4×2=84 \times 2 = 84×2=8 unshared electrons in total for oxygen atoms.
However, carbon does not have any unshared electrons because all of its valence electrons are involved in bonding.
Final Answer
The total number of unshared electrons in the CO2 Lewis structure is 4. These are all found in the lone pairs on the two oxygen atoms.
