Organic Chemistry: Resonance, Hybridization, and Molecular Geometry

Flashcards covering key organic chemistry concepts from the transcript, including electronegativity trends, resonance criteria, sp/sp2/sp3 hybridization, orbital overlap rules for sigma and pi bonds, and stereochemical wedge/dash representations.

Electronegativity Periodic Trend

The periodic trend where electronegativity increases from bottom to top and from the left-hand side to the right-hand side of the periodic table.

Octet Rule Criterion for Major Resonance Structure

A principle stating that a resonance structure fulfilling the octet requirement for all atoms is major compared to one that does not.

Formal Charge Criterion for Major Resonance Structure

A principle stating that a resonance structure with a lower amount of non-zero formal charges is major compared to structures with more formal charges.

$sp$ Hybridization

Hybridization generated when an atom has a total electron domain count of $2$ (bonding plus non-bonding domains), combining one $s$ and one $p$ atomic orbital to generate $2$ hybrid orbitals.

$sp^2$ Hybridization

Hybridization generated when an atom has a total electron domain count of $3$, producing $3$ hybrid orbitals.

$sp^3$ Hybridization

Hybridization generated when an atom has a total electron domain count of $4$, producing $4$ hybrid orbitals from one $s$ and three $p$ atomic orbitals.

Sigma Bond Formation

Bond formation resulting from hybrid orbitals (such as $sp$, $sp^2$, or $sp^3$) or atomic orbitals (such as hydrogen's $1s$ orbital) overlapping directly to form single bonds.

Pi Bond Formation

Bond formation resulting exclusively from the side-by-side overlap of unhybridized $p$ orbitals.

Wedge Bond Representation

A structural representation convention indicating that a bond or attached chemical group is facing towards the front (towards the viewer).

Dash Bond Representation

A structural representation convention indicating that a bond or attached chemical group is located at the back.

Triple Bond Geometry

A linear molecular geometry formed along a straight line with a bond angle of $180^\times$ (or $180^\text{ degrees}$).

Pi Bond Orbital Compatibility

The structural requirement that pi bonds can only form from side-by-side overlap of parallel $p$ orbitals, and cannot be formed by overlapping an $sp^3$ hybrid orbital with a $p$ orbital.