electronegativity

• What is electronegativity?

  The ability of atoms to attract bonding electrons
• Which element is the most electronegative?

  Fluorine
• What factors affect electronegativity?

  • Atomic radius: Smaller atoms are more electronegative
  • Nuclear charge: Higher positive charge increases electronegativity
  • Shielding: Inner shell electrons weaken attraction to outer electrons
• Why do smaller atoms have higher electronegativity?

  Electrons are closer to the nucleus
• How does nuclear charge influence electronegativity?

  A higher charge increases electrostatic attraction
• What role does shielding play in electronegativity?

  It reduces attraction between nucleus and outer electrons
• What are the trends in electronegativity across the periodic table?

  • Increases across a period
  • Decreases down a group
• Why does electronegativity increase across a period?

  Atomic radius decreases and nuclear charge increases
• Why does electronegativity decrease down a group?

  Atomic radius increases more than nuclear charge
• What causes polar bonds?

  Differences in electronegativity between bonded atoms
• What is a dipole in a polar bond?

  A separation of positive and negative charges
• What charge does the more electronegative atom acquire in a polar bond?

  A slight negative charge (δ-)
• Why is CCl4 non-polar despite having polar bonds?

  Dipoles cancel due to symmetric arrangement
• Why is CHCl3 polar?

  Dipoles do not cancel due to asymmetric arrangement
• How can you determine if a molecule has an overall dipole?

  Visualize its 3D structure and assess dipoles
• How does electronegativity difference predict bond type?

  • Difference = 0: Non-polar covalent (e.g., H2)
  • Difference 1.0 to 2.0: Polar covalent (e.g., HCl)
  • Difference > 2.0: Ionic (e.g., NaCl)
• What type of bond is formed when the electronegativity difference is less than 1.0?

  Non-polar covalent bond
• What type of bond is formed when the electronegativity difference is greater than 2.0?

  Ionic bond
• What happens in a polar covalent bond?

  Electrons are unequally shared between atoms
• What is an example of a polar covalent bond?

  HCl
• What is an example of an ionic bond?

  NaCl
• What character do most compounds exhibit regarding bond types?

  A mix of ionic and covalent character