Which of the following bonds is a nonpolar covalent bond?
1) H – F
2) N – F
3) F – CI
4) F -F
The Correct Answer and Explanation is:
The correct answer is:
4) F – F
Explanation:
A nonpolar covalent bond occurs when two atoms share electrons equally because they have the same electronegativity, meaning they have an identical ability to attract and hold onto electrons. In such a bond, the electron density is evenly distributed between the two atoms, resulting in no permanent dipole moment.
To understand why F – F is a nonpolar covalent bond, let’s break down the options:
1) H – F: The electronegativity of fluorine (F) is 3.98, while that of hydrogen (H) is 2.20. The difference in electronegativity (3.98 – 2.20 = 1.78) is significant. This creates a polar covalent bond, where fluorine attracts the shared electrons more strongly than hydrogen, resulting in a dipole moment with fluorine having a partial negative charge and hydrogen a partial positive charge.
2) N – F: Nitrogen (N) has an electronegativity of 3.04, and fluorine (F) has an electronegativity of 3.98. The electronegativity difference here is 0.94, which is also large enough to create a polar covalent bond, where fluorine attracts the shared electrons more strongly than nitrogen.
3) F – Cl: Fluorine (F) has an electronegativity of 3.98, and chlorine (Cl) has an electronegativity of 3.16. The electronegativity difference is 0.82, which is moderate enough to cause a polar covalent bond. Fluorine pulls the electron pair slightly more than chlorine, creating a dipole moment.
4) F – F: Fluorine atoms are identical and have the same electronegativity of 3.98. Since both atoms equally share the electrons, there is no difference in electron distribution, making this a nonpolar covalent bond. There is no dipole, and the electrons are shared equally.
Thus, the F – F bond is the only nonpolar covalent bond in the options provided.