Which of the following has only nonpolar covalent bonds? (Please explain your reasoning)
a. N2
b. CCl4
c. NaCl
d. CO
e. HI
The correct answer and explanation is:
The correct answer is a. N2.
Here’s the reasoning:
To determine which molecule has only nonpolar covalent bonds, we need to consider the types of bonds formed based on electronegativity differences between the atoms involved. A nonpolar covalent bond occurs when two atoms of the same element, or atoms with very similar electronegativities, share electrons equally.
Now, let’s look at the options:
- N2 (Nitrogen molecule): This molecule consists of two nitrogen atoms. Both atoms have the same electronegativity, meaning there is no difference in their ability to attract electrons. As a result, the electrons in the N≡N bond are shared equally, making this a nonpolar covalent bond. This molecule has only nonpolar covalent bonds.
- CCl4 (Carbon tetrachloride): In CCl4, carbon and chlorine have different electronegativities. Chlorine is more electronegative than carbon, which causes the electrons to be pulled slightly toward the chlorine atoms. While the molecule is overall nonpolar due to its symmetrical tetrahedral shape, the individual C-Cl bonds are polar covalent bonds because of the electronegativity difference.
- NaCl (Sodium chloride): NaCl forms an ionic bond between sodium (Na) and chlorine (Cl). Sodium donates an electron to chlorine, resulting in the formation of positive and negative ions, which are held together by electrostatic forces. This is not a covalent bond, so it does not fit the description of nonpolar covalent bonds.
- CO (Carbon monoxide): In CO, carbon and oxygen have a significant difference in electronegativity. Oxygen is more electronegative, so the electrons are shared unequally, resulting in a polar covalent bond.
- HI (Hydrogen iodide): In HI, iodine is more electronegative than hydrogen, causing the electrons in the H-I bond to be shared unevenly. This makes the bond a polar covalent bond.
Therefore, only N2 has nonpolar covalent bonds throughout.