Basic Concepts of Organic Chemistry — A/L Chemistry

What must I remember about Basic Concepts of Organic Chemistry?

• Carbon hybridization determines geometry: sp³ (tetrahedral, 109.5°, 4 σ-bonds), sp² (trigonal planar, 120°, 3 σ + 1 π-bond), and sp (linear, 180°, 2 σ + 2 π-bonds).
• Structural isomerism categories: chain isomerism (different carbon skeleton), position isomerism (different functional group position), and functional group isomerism.
• Stereoisomerism: geometric isomerism (cis/trans due to restricted rotation about C=C) and optical isomerism (non-superimposable mirror images containing a chiral carbon).
• Electronic effects: Inductive effect (+I electron-releasing by alkyl groups, -I electron-withdrawing by electronegative groups) and Resonance effect (delocalization of π-electrons/lone pairs).
• Reaction intermediates: carbocation stability follows 3° > 2° > 1° > methyl due to hyperconjugation and positive inductive (+I) alkyl effects.

Test yourself (1 minute)

1. IUPAC principal group priority hierarchy

   -COOH > -COOR > -CONH₂ > -CHO > >C=O > -OH > -NH₂ > C=C > C≡C > halides, -NO₂, alkyls.

2. What does an equimolar mixture of two enantiomers do to plane-polarized light?

   Enantiomers rotate plane-polarized light in equal and opposite directions; an equimolar mixture is an optically inactive racemic mixture.

3. What does homolytic fission produce, and what does heterolytic fission produce?

   Homolytic fission generates free radicals; heterolytic fission generates ions (electrophiles and nucleophiles).

Practise Basic Concepts of Organic Chemistry questions today

Source: NIE G.C.E. (A/L) Chemistry Syllabus (Unit 7)

What comes next?

Next in the syllabus

Where does Basic Concepts of Organic Chemistry fit in the syllabus?

Grade 12 · Term 3