Ch 14Basic Principles of Organic Chemistry — Class 11 Chemistry, concept-first.

Among all the elements of the periodic table, carbon alone is able to form an almost unlimited variety of compounds -- everything from methane, with its single carbon atom, up to deoxyribonucleic acid…

Before any of a molecule's chemistry can be discussed, it first has to be represented clearly on paper.

A condensed formula is a deliberate simplification of the full structural formula: rather than drawing out every single covalent-bond dash, some or all of the bonds are simply hidden, and wherever an…

A bond-line (or zig-zag) formula goes a step further than a condensed formula by dropping the element symbols for carbon and hydrogen entirely, keeping only the bond lines themselves.

Because most real organic molecules are genuinely three-dimensional in shape, chemists use four different conventions to project a 3-D molecule onto flat paper, each suited to a slightly different pur…

With so many different organic structures to keep track of, chemists needed a systematic way to relate a molecule's structure to its chemical behaviour -- and that need is exactly what motivates class…

Classification by carbon skeleton looks purely at how a molecule's own carbon atoms are bonded to one another -- this bonded network is called the carbon skeleton, and it is what fundamentally decides…

Classification by functional group instead looks at which specific, reactive group of atoms a molecule carries -- and that functional group is defined precisely as the part of an organic molecule that…

Having established how to draw and how to classify organic molecules, the next essential skill is being able to NAME them -- and to name each one so precisely and unambiguously that any chemist, anywh…

As organic chemistry developed historically, a new compound was typically given its own individual, one-off name as soon as it was discovered or isolated, well before any systematic naming scheme exis…

As organic chemistry's known compounds multiplied rapidly, and their structures grew steadily more complex, simply inventing a fresh trivial name for every new compound stopped being workable -- diffe…

The homologous series of straight-chain alkanes provides the PARENT HYDROCARBON building block for every aliphatic IUPAC name -- so before any branching, functional group, or ring can be named, the st…

Any branch or side chain hanging off a saturated parent hydrocarbon is itself an ALKYL group (an alkyl substituent).

Naming alkenes (carbon-carbon double bonds) and alkynes (carbon-carbon triple bonds) uses every rule already given for alkanes, PLUS several additional rules specific to the multiple bond itself.

A saturated MONOCYCLIC hydrocarbon (a single-ring, fully saturated compound) is named simply by attaching the prefix 'cyclo-' to the name of the OPEN-CHAIN alkane with the same number of carbon atoms…

IUPAC names for compounds carrying one or more functional groups build on everything already established for the underlying hydrocarbon skeleton, adding the functional group itself in as a prefix and/…

Naming a substituted benzene ring follows its own set of conventions, layered by how many substituents are present.

Isomerism is the phenomenon in which two or more genuinely DIFFERENT compounds nonetheless share exactly the same molecular formula; any two (or more) such compounds are called isomers of one another.…

Compounds that share the same molecular formula but have a genuinely different structural formula are called structural isomers of one another, and the overall phenomenon is called structural isomeris…

Every organic reaction, at bottom, comes down to one or more of a molecule's covalent bonds being broken while one or more new covalent bonds are simultaneously formed, usually because a second reacta…

A covalent bond -- a shared pair of electrons holding two atoms together -- can be broken (undergo 'cleavage' or 'fission') in one of two distinct ways.

Organic reagents are classified into two broad types, based purely on whether they DONATE or ACCEPT electrons when they react with a substrate.

Beyond simply classifying reagents, organic chemistry also needs a way to explain WHY particular parts of a substrate molecule end up being electron-rich or electron-deficient in the first place, sinc…

A covalent bond formed between two atoms of genuinely DIFFERING electronegativity is, by definition, a polar covalent bond -- the C-Cl bond is the chapter's running example, since chlorine is consider…

Resonance theory applies whenever a molecule's Lewis structure contains a CONJUGATED system of pi bonds -- that is, two or more multiple bonds alternating with single bonds along a chain or ring -- or…

The existence of resonance within a conjugated system frequently ends up developing a real, ground-state POLARITY in the overall molecule -- and this specific polarity, arising directly from the inter…

The ELECTROMERIC effect is, by contrast with the inductive and resonance effects covered above, a genuinely TEMPORARY electronic effect -- one that is shown ONLY by multiple-bonded groups, and only un…

Hyperconjugation is a further, genuinely PERMANENT electronic effect (unlike the electromeric effect, but like the inductive and resonance effects), and it specifically explains the observed relative…