Question

Determine if the following covalent bonds between atoms of these nonmetals are polar or nonpolar by calculating the difference in electronegativity values or EN (electronegativity number).

1. H-Br
2. K-Cl
3. N-H
4. S-O
5. P-O
6. Si-F
7. O-H
8. P-Cl.

Answer 1

If a bond is polar or nonpolar, the difference in electronegativity (EN) between the two atoms is calculated. Bonds with EN differences less than 0.5 are nonpolar covalent, between 0.5 to 1.9 are polar covalent, and more than 1.9 are typically ionic. Based on this, most bonds listed are polar covalent, except K-Cl which is ionic.

Step-by-step explanation:

To determine if a covalent bond is polar or nonpolar, we need to calculate the difference in electronegativity (EN) between the two bonded atoms. A bond is considered nonpolar covalent if the EN difference is less than 0.5, polar covalent if the EN difference is between 0.5 to 1.9, and ionic if the EN difference is more than 1.9. Below are the assessments based on these guidelines:

• H-Br: Polar covalent (≈0.7 difference in EN)
  
• K-Cl: Ionic (EN difference > 1.9 since K is a metal and Cl is a nonmetal)
  
• N-H: Polar covalent (≈0.9 difference in EN)
  
• S-O: Polar covalent (≈1.0 difference in EN)
  
• P-O: Polar covalent (≈1.4 difference in EN)
  
• Si-F: Polar covalent (≈1.7 difference in EN)
  
• O-H: Polar covalent (≈1.4 difference in EN)
  
• P-Cl: Polar covalent (≈0.5 difference in EN)

Note that while the K-Cl bond was listed, it is actually an ionic bond, not a covalent one. This is because K (Potassium) is a metal and these types of bonds between metals and nonmetals (like Chlorine) are usually ionic due to a high EN difference.