Organic Chemistry Chapter 2 Review: Polar Covalent Bonds, Acids, and Bases

Vocabulary flashcards covering electronegativity, bond types, intermolecular forces, resonance, formal charge, and Brønsted-Lowry and Lewis acid-base theories from Chapter 2 of John McMurry's Organic Chemistry.

Electronegativity

A measure of the ability of an atom in a molecule to draw electron density towards itself.

Inductive effect

The shifting of electrons in a $\sigma$ bond caused by differences in electronegativity.

Pure (nonpolar) covalent bond

A bond type where electrons are shared equally, typically involving an electronegativity difference ($\Delta EN$) of $0.0$ to $0.4$.$

Polar covalent bond

A bond type where electrons are shared unequally, typically involving an electronegativity difference ($\Delta EN$) of $0.4$ to $2.0$.$

Ionic bond

A bond type where electrons are transferred, typically involving an electronegativity difference ($\Delta EN$) of $2.0+$.$

Intermolecular forces (IMFs)

The forces of attraction between molecules that explain physical properties of liquids, such as boiling points.

London dispersion forces

The weakest intermolecular forces caused by temporary charges (or dipoles) in an atom or molecule.

Dipole-dipole attractions

Intermolecular forces between polar molecules based on permanent dipoles, which are stronger than London forces.

Hydrogen bonding

A strong dipole-dipole force observed when $H$ is bonded to $N$, $O$, or $F$.

Ion-dipole attraction

An attractive force occurring between ionic charges and polar molecules; it is stronger than hydrogen bonding but weaker than pure ionic attractions.

Ionic attraction forces

The strongest attractive force involving full charges from both a cation and an anion; also referred to as salt bridges.

Resonance structure

One of two or more Lewis structures for a single molecule that differ only in the positions of their electrons.

Formal charge (FC)

The charge on an individual atom within a Lewis structure, calculated as: $\text{FC} = \text{valence electrons} - \text{lines} - \text{dots}$.

Arrow pushing

The convention of drawing arrows to show electron movement from an area of higher electron density to lower electron density in resonance structures.

Brønsted-Lowry acid

A substance that acts as a proton ($H^+$) donor.

Brønsted-Lowry base

A substance that acts as a proton ($H^+$) acceptor.

Conjugate base

The species formed after an acid loses an $H^+$ ion; it has one less hydrogen than its parent acid.

Conjugate acid

The species formed after a base gains an $H^+$ ion; it has one more hydrogen than its parent base.

Acid ionization constant ($K_a$)

A value that details how strong an acid is; a higher value corresponds to a stronger acid.

$$p K_a$$

The negative logarithm of the acid ionization constant, defined as $p K_a = -\text{log}(K_a)$. A higher value corresponds to a weaker acid.

CARDIO

An acronym used to compare acid or base strength based on Charge, Atomic radius, Resonance, Dipole, Inductive effect, and Orbital.

Lewis base

A substance that can donate a pair of electrons, also known as a nucleophile.

Lewis acid

A substance that can accept a pair of electrons, also known as an electrophile.