Potassium carbonate (K2CO3) has one potassium atom bonded to carbon, and that carbon is also bonded to three oxygens. Their electronegativities are shown in the list:
K: 0.82
C: 2.55
O: 3.44
How would you describe the bonds (K–C and C–O) in this molecule?
a) K–C is polar covalent, and C–O is polar covalent.
b) K–C is ionic, and C–O is polar covalent.
c) K–C is polar covalent, and C–O is nonpolar covalent.
d) K–C is ionic, and C–O is nonpolar covalent.
b) K–C is ionic, and C–O is polar covalent.
To determine the type of bonds between atoms in a molecule, we can look at the difference in electronegativities between the atoms involved. The greater the difference, the more polar or ionic the bond will be.
In this case, the electronegativity difference between potassium (K) and carbon (C) is 2.55 - 0.82 = 1.73, which is considered relatively large. This indicates that the K-C bond is polar covalent.
Likewise, the electronegativity difference between carbon (C) and oxygen (O) is 3.44 - 2.55 = 0.89, which is also relatively large. This suggests that the C-O bond is polar covalent as well.
Therefore, the correct answer is:
a) K–C is polar covalent, and C–O is polar covalent.
To determine the nature of the bonds in potassium carbonate (K2CO3), we need to consider the difference in electronegativity between the atoms involved.
The electronegativity values are as follows:
K: 0.82
C: 2.55
O: 3.44
When the difference in electronegativity between two atoms is less than 0.5, the bond between them is considered nonpolar covalent.
When the difference in electronegativity is between 0.5 and 1.7, the bond is considered polar covalent.
When the difference in electronegativity is greater than 1.7, the bond is considered ionic.
Let's analyze the bonds in potassium carbonate (K2CO3):
1. K–C bond:
The electronegativity difference between potassium (K) and carbon (C) is 2.55 - 0.82 = 1.73, which is greater than 1.7. Therefore, the K–C bond is considered ionic.
2. C–O bonds:
The electronegativity difference between carbon (C) and oxygen (O) is 3.44 - 2.55 = 0.89, which is between 0.5 and 1.7. Therefore, the C–O bonds are considered polar covalent.
Therefore, the correct answer is b) K–C is ionic, and C–O is polar covalent.