Week 2

Chemical reactions

Processes that occur as a result of giving, taking, and/or sharing of electrons.

Covalent bond

A type of chemical bond where electrons are shared between atoms.

Polarity

The presence of partial charges within a molecule, leading to electron transfer among atoms.

Saturated hydrocarbons

Nonreactive compounds with no polarity in C-C and C-H bonds.

Electron density

The distribution of electrons within a bond or molecule.

Electronegativity

The ability of an atom to attract electrons towards itself in a chemical bond.

Electrophiles

Positively charged species that react with polar organic molecules.

Nucleophiles

Negatively charged species that react with polar organic molecules.

Substituent

An atom or group of atoms attached to a molecule.

Electron displacement effect

Effects produced by the movement of electrons, leading to the development of polarities on atoms.

Inductive effect

The transmission of charge through a chain of atoms in a molecule by electrostatic induction.

Steric effect

The effect of crowding in a molecule on its reactivity.

Electronic effects

Effects that complicate chemical reactions and can stabilize or affect the behavior of a molecule.

-I groups

Electron-withdrawing groups that repel or withdraw electrons from a carbon atom.

+I groups

Electron-releasing groups that donate or release electrons towards a carbon atom.

Relative inductive effects

The experimentally measured effects of different atoms or groups on electron density, compared to hydrogen.

Inductive Effect

The effect of electron-withdrawing or electron-donating groups on the stability of a molecule, depending on the charge present on the atom and the type of groups bonded to it.

Mesomeric Effect

Also known as resonance effect, it occurs when a molecule can be represented by two or more structures that differ only in the arrangement of electrons. The compounds showing mesomeric effect are more stable than those that do not.

Localized Electrons

Electrons that are restricted to a particular region, either belonging to a single atom or confined to a bond between two atoms.

Delocalized Electrons

Electrons shared by more than two atoms, resulting in resonance. Delocalization occurs when all the atoms sharing the delocalized electrons lie in or close to the same plane.

Resonance Contributors

Different structures that represent the resonance effect in a molecule. The resonance hybrid is a composite of these contributors, with the location of lone-pair and pi electrons differing.

Lewis Structures

Diagrams that show the bonding between atoms in a molecule, as well as the lone pairs of electrons. Also known as Lewis dot formulas or electron dot structures.

What causes chemical reactions to occur? Answer

The giving, taking, and/or sharing of electrons.

How does polarity within a molecule affect its behavior? Answer

It leads to electron transfer among atoms, resulting in different behavior compared to non-polar compounds.

Why are saturated hydrocarbons nonreactive? Answer

Due to the lack of polarity in C-C and C-H bonds.

What causes charged species to react with polar organic molecules? Answer

An imbalance in electron density or polarity.

How can elements with higher electronegativity affect the reactivity of an organic molecule? Answer

They can change the electron density around the molecule and make it more reactive.

What factors influence electron availability in organic molecules? Answer

Electron displacement effects or electronic effects.

How do substituents affect reactivity? Answer

Through electronic and steric effects.

What can electronic effects do to a molecule? Answer

Stabilize it, affect its volatility, and influence its acidity or basicity.

What is the inductive effect? Answer

A type of electronic effect where partial polarities are developed on atoms joined by a single covalent bond.

How does the inductive effect change with distance from the source atom? Answer

It decreases with distance.

What are the two types of inductive effect? Answer

Electron-withdrawing (-I) and electron-releasing (+I).

How are relative inductive effects measured? Answer

With reference to hydrogen.

How can the inductive effect determine the stability of a molecule? Answer

Depending on the charge and type of groups bonded to an atom.

What is the resonance effect? Answer

When a molecule can be represented by multiple structures that differ in electron arrangement.

What causes the resonance effect? Answer

The interaction of pi-bonds separated by a single bond or a pi-bond and a lone pair of electrons.

What are the different structures resulting from the resonance effect called? Answer

Resonance structures.

What are the two factors influencing electron availability in organic molecules? Answer

Inductive effect and resonance effect.

What is the mesomeric effect? Answer

A permanent effect that makes compounds more stable.

Is the mesomeric effect negative or positive for electron-withdrawing groups? Answer

Negative (-M).

Is the mesomeric effect negative or positive