Bonding fundamentals: Polarity, Electronegativity, Induction, Formal Charges & Resonance

Apuntes

[Diapositiva 1] CHAPTER 2 Polar Covalent Bonds Acids and Bases Electronegativity & Bond Polarity Dipole Moments Formal Charges Resonance Brønsted–Lowry & Lewis Acids/Bases Noncovalent Interactions OpenStax Organic Chemistry | Access for free at openstax.org [Diapositiva 2] The Bonding Spectrum: Why electrons aren't always shared equally Covalent Bond X–X (same element) Electrons shared equally. Symmetrical distribution. C-H are considered nonpolar covalent EN difference < 0.5 e.g. C–C in ethane Polar Covalent X–Y (different elements) Electrons pulled toward more electronegative atom. Usually consists of Nonmetals and/or Metalloids, but not always. EN difference 0.5–2.0 e.g. C–O, C–N, C–Cl Ionic Bond Metal + Nonmetal Complete electron transfer. Forms ions. EN difference > 2.0 e.g. NaCl (Na⁺ and Cl⁻) ← More covalent character More ionic character → [Diapositiva 3] Electronegativity (EN) Values — Pauling Scale F EN = 4.0 Most electronegative O EN = 3.5 Very high EN (key in organics) N EN = 3.0 High EN (amines, amides) Cl EN = 3.0 High EN (halogens) C EN = 2.5 Intermediate (organic center) H EN = 2.1 Similar to C (C–H ~ nonpolar) Li EN = 1.0 Low EN (electron donor) Cs EN = 0.7 Least el...