Problem 101 - Chemistry: An Atoms-Focused Approach

Question

Which of the following bonds are polar? $\mathrm{C}-\mathrm{Se}, \mathrm{C}-\mathrm{O}\( \)\mathrm{Cl}-\mathrm{Cl}, \mathrm{O}=\mathrm{O}, \mathrm{N}-\mathrm{H}, \mathrm{C}-\mathrm{H} .$ In the bond or bonds that you selected, which atom has the greater electronegativity?

Step-by-Step Solution

Answer

Answer: The polar bonds are C-O, N-H, and C-H. In these polar bonds, Oxygen has greater electronegativity in the C-O bond, Nitrogen in the N-H bond, and Carbon in the C-H bond.

Step 1: Determine the Electronegativity of Each Atom

To determine the polarity of each bond, we must first find the electronegativity of each atom involved in the bond. Using a reference table or a periodic table, obtain electronegativity values for Carbon (C), Selenium (Se), Oxygen (O), Chlorine (Cl), Nitrogen (N), and Hydrogen (H). Here are the approximate electronegativity values for these atoms: C: 2.5 Se: 2.4 O: 3.5 Cl: 3.2 N: 3.0 H: 2.1

Step 2: Calculate the Electronegativity Difference for Each Bond

Now that we have the electronegativity values, we can calculate the electronegativity difference for each of the given bonds: C-Se: |2.5 - 2.4| = 0.1 C-O: |2.5 - 3.5| = 1.0 Cl-Cl: |3.2 - 3.2| = 0 (Since it's the same element) O=O: |3.5 - 3.5| = 0 (Same element) N-H: |3.0 - 2.1| = 0.9 C-H: |2.5 - 2.1| = 0.4

Step 3: Determine the Bond's Polarity

Based on the electronegativity difference values calculated in step 2, we can determine whether a bond is polar or not (with a general threshold of 0.4 as mentioned above): C-Se: Nonpolar (0.1 < 0.4) C-O: Polar (1.0 > 0.4) Cl-Cl: Nonpolar (0 < 0.4) O=O: Nonpolar (0 < 0.4) N-H: Polar (0.9 > 0.4) C-H: Polar (0.4 > 0.4)

Step 4: Identify the Atom with Greater Electronegativity in Polar Bonds

Now that we have identified the polar bonds, we can determine which atom in each bond has the greater electronegativity: C-O: O (3.5 > 2.5) N-H: N (3.0 > 2.1) C-H: C (2.5 > 2.1) #Conclusion# Out of the given bonds, the polar bonds are C-O, N-H, and C-H. In these polar bonds, Oxygen has the greater electronegativity in the C-O bond, Nitrogen in the N-H bond, and Carbon in the C-H bond.