CHEM 201 - Lewis Diagrams and Reactions

These flashcards cover key concepts related to Lewis diagrams, chemical reactions, and isomerism as discussed in the lecture.

What are Lewis diagrams used for?

To describe reactions and visualize the transfer or sharing of electrons.

What do curly arrows represent in Lewis diagrams?

The movement of electrons between atoms.

In a reaction, where do electrons generally move from and to?

From high electron density to low electron density.

What is required for the formation of ionic compounds?

A large enough (negative) lattice enthalpy to compensate for ionization energy and electron affinity.

What does the reaction of sodium (Na) with oxygen (O2) produce?

Disodium oxide (Na2O).

What happens when disodium oxide reacts with water?

It produces sodium hydroxide (NaOH) and gives a pink color to the indicator.

What are constitutional isomers?

Compounds that have the same molecular formula but different atom-to-atom connectivity.

How do molecular formulas differ from structural formulas?

Molecular formulas provide no information about connectivity, while structural formulas do.

What are Lewis diagrams used for?

To describe reactions and visualize the transfer or sharing of electrons.

What do curly arrows represent in Lewis diagrams?

The movement of electrons between atoms.

In a reaction, where do electrons generally move from and to?

From high electron density to low electron density.

What is required for the formation of ionic compounds?

A large enough (negative) lattice enthalpy to compensate for ionization energy and electron affinity.

What are the primary types of isomers?

Isomers can be categorized into two main types: constitutional isomers and stereoisomers.

What are constitutional isomers?

Compounds that have the same molecular formula but different atom-to-atom connectivity.

How do molecular formulas differ from structural formulas?

Molecular formulas provide no information about connectivity, while structural formulas do.

What should be included in a condensed structural formula?

A representation of the connectivity of atoms without showing all single bonds and electron lone pairs.

What is a heteroatom?

Any atom other than carbon (C) and hydrogen (H).

What is a functional group?

A specific group of atoms within a molecule that is responsible for its characteristic chemical reactions.

What is an alcohol functional group?

An -OH (hydroxyl) group attached to a saturated carbon atom.

What are stereoisomers?

Isomers that have the same molecular formula and atom-to-atom connectivity but differ in the spatial arrangement of their atoms.

In chemical notation, what do square brackets \"[]\" around a structural formula often indicate?

They typically indicate that the enclosed species is an ion and its overall charge, especially for polyatomic ions or complex ions.

What are Lewis diagrams used for?

To represent the valence electrons of an atom and visualize the formation of chemical bonds, as well as the transfer or sharing of electrons in molecular structures and reactions.

What do curly arrows represent in Lewis diagrams?

The movement of electron pairs (either lone pairs or bonding pairs) during chemical reactions, showing the flow from an electron-rich site to an electron-poor site.

In a reaction, where do electrons generally move from and to?

In chemical reactions, electrons generally move from areas or species with high electron density (e.g., nucleophiles, lone pairs, pi bonds) to areas or species with low electron density (e.g., electrophiles, empty orbitals).

What is required for the formation of ionic compounds?

For the formation of stable ionic compounds, a sufficiently large and negative lattice enthalpy is required to energetically compensate for the endothermic processes of ionization energy (removing electrons from the metal) and the electron affinity (adding electrons to the nonmetal).

What are the primary types of isomers?

Isomers are molecules that have the same molecular formula but differ in the arrangement of their atoms. They are fundamentally categorized into two primary types: constitutional isomers and stereoisomers.

What are constitutional isomers?

Constitutional isomers (also known as structural isomers) are compounds that share the same molecular formula but possess different atom-to-atom connectivity or bonding arrangements.

How do molecular formulas differ from structural formulas?

Molecular formulas (e.g., C2H6O) only indicate the types and number of atoms in a molecule, providing no information about their arrangement or connectivity. In contrast, structural formulas (e.g., ethanol CH3CH2OH vs. dimethyl ether CH3OCH3) explicitly show the atom-to-atom connections within the molecule, revealing its specific structure.

What should be included in a condensed structural formula?

A condensed structural formula represents the connectivity of atoms in a molecule by grouping hydrogen atoms with the carbons they are attached to, and often omitting single bonds and electron lone pairs, thereby simplifying the full structural drawing while retaining connectivity information.

What is a heteroatom?

In organic chemistry, a heteroatom is any atom in an organic molecule that is not carbon (C) or hydrogen (H). Common heteroatoms include oxygen (O), nitrogen (N), sulfur (S), phosphorus (P), and the halogens (F, Cl, Br, I).

What is a functional group?

A functional group is a specific arrangement of atoms within a molecule that is responsible for the molecule's characteristic chemical properties and reactions, largely influencing its reactivity.

What is an alcohol functional group?

An alcohol functional group consists of a hydroxyl group (-OH) covalently bonded to a saturated carbon atom (an sp^3 hybridized carbon atom).

What is a carboxylic acid functional group?

A carboxylic acid functional group is characterized by a carboxyl group (R-COOH), which consists of a carbon atom double-bonded to an oxygen atom (carbonyl) and single-bonded to a hydroxyl group (-OH).

What is an ester functional group?

An ester functional group is derived from a carboxylic acid and an alcohol. It contains a carbonyl group (-C=O) bonded directly to an oxygen atom, which is then bonded to another carbon-containing group (R-COO-R').

What is an aldehyde functional group?

An aldehyde functional group contains a carbonyl group (-C=O) where the carbon atom is bonded to at least one hydrogen atom and an alkyl or aryl group (or a second hydrogen atom in formaldehyde) (R-CHO).

What is a ketone functional group?

A ketone functional group contains a carbonyl group (-C=O) where the carbon atom is bonded to two carbon-containing groups (alkyl or aryl groups) (R-CO-R').

What are stereoisomers?

Stereoisomers are isomers that share the same molecular formula and atom-to-atom connectivity but differ in the three-dimensional spatial arrangement of their atoms in space. They are not interconvertible by simple bond rotation.

In chemical notation, what do square brackets "[]" around a structural formula often indicate?

In chemical notation, square brackets ('[]') around a structural formula frequently indicate that the enclosed species is an ion, denoting its overall charge. This is particularly common for polyatomic ions (e.g., ammonium ion $[NH4]^ +$) or complex ions (e.g., tetrachloroplatinate(II) ion $[PtCl4]^ {2-}).