Alkene — structure, naming, and key reactivity?

A carbon–carbon double bond. Named with the suffix -ene. The electron-rich pi bond acts as a nucleophile, so alkenes undergo electrophilic addition: hydrohalogenation, halogenation, and hydration.

Alkyne — structure, naming, and key reactivity?

A carbon–carbon triple bond. Named with the suffix -yne. It also undergoes electrophilic addition, and a terminal alkyne's C–H is acidic enough to be deprotonated by sodium amide, giving a nucleophilic acetylide ion.

Alcohol — structure, naming, and key reactivity?

A hydroxyl group (–OH) bonded to an sp3 carbon. Named with the suffix -ol, or the prefix hydroxy- when a higher-priority group is present. Alcohols are weakly acidic, nucleophilic at oxygen, and can be oxidized or converted into leaving groups.

What are the oxidation products of primary, secondary, and tertiary alcohols?

A primary alcohol oxidizes to an aldehyde and then on to a carboxylic acid. A secondary alcohol oxidizes to a ketone. A tertiary alcohol resists oxidation, because its carbinol carbon bears no hydrogen to remove.

Phenol — structure and key property?

A hydroxyl group attached directly to a benzene ring. It is far more acidic than an ordinary alcohol, because the phenoxide ion left after deprotonation is stabilized by resonance into the aromatic ring.

Ether — structure, naming, and key reactivity?

An oxygen bonded to two carbon groups (R–O–R'). Named by treating the smaller side as an alkoxy substituent, as in methoxyethane. Ethers are relatively unreactive, which is why they are widely used as solvents.

Epoxide — structure and key reactivity?

A three-membered ring containing one oxygen — a cyclic ether. Its ring strain makes it far more reactive than an ordinary ether, so nucleophiles open the ring readily.

Thiol — structure, naming, and key reactivity?

An –SH group, the sulfur analogue of an alcohol. Named with the suffix -thiol. Thiols are more acidic and more nucleophilic than alcohols, and two of them oxidize to form a disulfide (S–S) bond.

Amine — structure, naming, and key property?

A nitrogen bonded to one, two, or three carbon groups, making it primary, secondary, or tertiary. Named with the suffix -amine or the prefix amino-. The nitrogen lone pair makes amines both basic and nucleophilic.

Aldehyde — structure, naming, and key reactivity?

A carbonyl carbon bearing at least one hydrogen, so it sits at the end of a chain. Named with the suffix -al. It undergoes nucleophilic addition and is readily oxidized to a carboxylic acid.

Ketone — structure, naming, and key reactivity?

A carbonyl carbon bonded to two other carbons. Named with the suffix -one, or the prefix oxo- when a higher-priority group is present. It undergoes nucleophilic addition but is not easily oxidized further.

Why is an aldehyde more reactive than a ketone toward nucleophilic addition?

A ketone's carbonyl carbon carries two electron-donating alkyl groups, which reduce its partial positive charge and crowd the approaching nucleophile. An aldehyde has only one, so it is both more electrophilic and less hindered.

Carboxylic acid — structure, naming, and key property?

A carbonyl carbon that also bears a hydroxyl group (–COOH). Named with the suffix -oic acid. It is genuinely acidic, because the carboxylate left after deprotonation is resonance-stabilized across two oxygens.

Ester — structure, naming, and key reactivity?

A carbonyl bonded to an –OR group (RCOOR'). Named as alkyl alkanoate, such as ethyl ethanoate. Esters form from a carboxylic acid and an alcohol under acid catalysis, and hydrolyze back — under base that hydrolysis is saponification.

Amide — structure, naming, and key property?

A carbonyl bonded to a nitrogen. Named with the suffix -amide. It is the least reactive carboxylic acid derivative, because the nitrogen lone pair donates into the carbonyl. The peptide bonds linking amino acids are amides.

Acid chloride (acyl chloride) — structure, naming, and key reactivity?

A carbonyl bonded to a chlorine. Named with the suffix -oyl chloride, as in ethanoyl chloride. It is the most reactive carboxylic acid derivative, because chloride is an excellent leaving group.

Acid anhydride — structure, naming, and key reactivity?

Two acyl groups joined by a shared oxygen (RCO–O–COR). Named by replacing 'acid' with 'anhydride', as in ethanoic anhydride. It is the second most reactive carboxylic acid derivative, after acid chlorides.

Rank the carboxylic acid derivatives from most to least reactive.

Acid chloride, then anhydride, then ester, then amide. Reactivity tracks how good the leaving group is, so a derivative can be converted into any one below it in the series but not directly into one above it.

Nitrile — structure, naming, and key reactivity?

A carbon triple-bonded to nitrogen (–C≡N). Named with the suffix -nitrile. Complete hydrolysis converts a nitrile into a carboxylic acid, and reduction converts it into a primary amine.

Imine (Schiff base) — structure and how it forms?

A carbon–nitrogen double bond (C=N). It forms when an aldehyde or ketone condenses with a primary amine and loses water. The reaction is fastest under mildly acidic conditions.

Alkyl halide (haloalkane) — structure, naming, and key reactivity?

A halogen bonded to an sp3 carbon. Named with the prefix fluoro-, chloro-, bromo-, or iodo-. The polarized C–X bond and the good halide leaving group make it the standard substrate for substitution and elimination reactions.

How does benzene's reactivity differ from an alkene's?

Benzene's pi electrons are delocalized around the ring, and that aromatic stabilization would be lost in an addition product. So benzene undergoes electrophilic aromatic substitution, which preserves the ring, rather than the addition typical of alkenes.

What is the difference between a hemiacetal and an acetal?

A hemiacetal carbon bears one –OH and one –OR group, and forms when one equivalent of alcohol adds to an aldehyde or ketone. An acetal carbon bears two –OR groups, formed when a second alcohol replaces the –OH under acid catalysis.

What is the IUPAC priority order used to choose the suffix in a name?

From highest to lowest: carboxylic acid, anhydride, ester, acid halide, amide, nitrile, aldehyde, ketone, alcohol, amine, then alkene or alkyne, then alkane. The highest-priority group becomes the suffix and takes the lowest locant; the rest are named as prefixes. Ethers and halogens are always prefixes, never suffixes.

What are the most important functional groups in organic chemistry?

The carbonyl-containing groups do the most work: aldehydes, ketones, carboxylic acids, esters, amides, acid chlorides, and anhydrides. Alongside them, alcohols, amines, ethers, alkenes, alkynes, and alkyl halides account for most of the reactions in a first-year course.

How do you rank functional groups for IUPAC naming?

The highest-priority group present becomes the suffix and gets the lowest locant. The common order, from highest to lowest, is carboxylic acid, ester, amide, nitrile, aldehyde, ketone, alcohol, amine, then alkene or alkyne, then alkane. Lower-priority groups are named as prefixes.

What is the best way to study organic chemistry functional groups?

Practice recognition in both directions — structure to name and name to structure — and space the reviews so the early groups stay sharp once reaction mechanisms start. Cram can turn your organic chemistry notes into flashcards with AI and schedule each card with spaced repetition.

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Organic Chemistry Functional Groups flashcards

This deck covers the functional groups an organic chemistry course expects you to recognize on sight: hydrocarbons with pi bonds, alcohols, phenols, ethers, epoxides, thiols, amines, the carbonyl pair (aldehydes and ketones), the carboxylic acid derivatives (acid chlorides, anhydrides, esters, amides), nitriles, imines, and alkyl halides. Each card gives the structure, the IUPAC suffix or prefix used to name it, and the reaction behavior the group is known for.

Organic chemistry is taught around functional groups because they determine everything downstream: which reagent attacks where, what a molecule is named, how acidic a proton is, and where a group sits in an oxidation sequence. Exams almost never ask you to define a group in isolation — they show a structure and ask for the product, the name, or the more reactive of two compounds, all of which start with correctly identifying what you are looking at.

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How to study this deck

Order the carboxylic acid derivatives once and keep them in that order forever: acid chloride, anhydride, ester, amide. Reactivity falls down the list as the leaving group gets worse, and any derivative can be converted into one lower on the list but not directly into one higher.
Learn the carbon oxidation ladder as a single sequence — alkane, alcohol, aldehyde, carboxylic acid — so oxidation and reduction questions become a matter of counting steps rather than memorizing isolated reagents.
Draw each group rather than reading it. Sketch the structure from the name, then name the structure back from your own drawing; the gap between recognizing a group and producing it is where most exam points are lost.

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