Overview
This lecture explains the difference between polar and non-polar covalent bonds, focusing on how electrons are shared based on electronegativity.
Covalent Bonds and Electron Sharing
- Covalent bonds involve the sharing of electrons between atoms to satisfy the octet rule.
- In non-polar covalent bonds, electrons are shared equally between the atoms.
- In polar covalent bonds, electrons are shared unequally between the atoms.
Role of Electronegativity
- Electronegativity is the tendency of an atom to attract electrons.
- The greater the difference in electronegativity between two atoms, the more unequally electrons are shared.
- Atoms with similar electronegativity share electrons equally; those with differing electronegativity share them unequally.
Examples of Bond Polarity
- A bond between two chlorine atoms (Cl–Cl) is non-polar because both have the same electronegativity.
- A bond between carbon and oxygen (C–O) is polar because oxygen is more electronegative, pulling electrons closer to itself.
- The carbon-hydrogen (C–H) bond is considered non-polar since their electronegativity difference is negligible.
Visualizing Polarity
- In polar bonds, arrows can show the direction electrons are pulled—toward the more electronegative atom.
- Unequal sharing in polar bonds means electrons spend more time near the more electronegative atom.
Key Terms & Definitions
- Covalent bond — a chemical bond where two atoms share electrons.
- Polarity — property describing unequal (polar) or equal (non-polar) sharing of electrons in a bond.
- Electronegativity — an atom’s capability to attract shared electrons in a bond.
- Non-polar covalent bond — bond with equal electron sharing due to identical or very similar electronegativity.
- Polar covalent bond — bond with unequal electron sharing due to different electronegativity values.
Action Items / Next Steps
- Review the concept of electronegativity for deeper understanding.
- Study dipoles in more detail in future lessons.