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Bond Fission and Reagent Types
Homolytic fission: each atom takes one electron, radicals (odd e-) named. Heterolytic: both electrons stay with one atom, ions (carbocation / carbanion named). Reagents: electrophile wants electrons (Br-d+ in Br2/alkene school). Nucleophile has a pair to give (OH-, NH3, CN- named as school examples). Free-radical named in methane + Cl2 (light) as a type, not a chain-weapon story. Meaning: the arro
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Bond Fission and Reagent Types
What is it?
Homolytic fission: each atom takes one electron, radicals (odd e-) named. Heterolytic: both electrons stay with one atom, ions (carbocation / carbanion named). Reagents: electrophile wants electrons (Br-d+ in Br2/alkene school). Nucleophile has a pair to give (OH-, NH3, CN- named as school examples). Free-radical named in methane + Cl2 (light) as a type, not a chain-weapon story. Meaning: the arrow in a mechanism follows the pair (school curly arrows if asked). Homolytic: one e each — radicals; heterolytic: both e to one atom — ion pair. Convert between formula types before naming; longest chain and lowest locants decide IUPAC marks.
In simple words
- Homolytic fission: each atom takes one electron, radicals (odd e-) named.
- 1. FISSION: UV on Cl2: radicals (named initiation).
- 2. Nu AND E+: OH- attacks carbon of C-Br (later SN2 idea).
- Exam reminder: Exam pair: nucleophile: electron-pair donor (OH-) electrophile: electron-pair acceptor (H+, Br2 with alkenes) homolytic fission makes radicals
Important terms
BOND FISSION AND REAGENT TYPES: Homolytic fission: each atom takes one electron, radicals (odd e-) named.
1. FISSION: UV on Cl2: radicals (named initiation).
2. Nu AND E+: OH- attacks carbon of C-Br (later SN2 idea).
What you should learn
- Explain bond fission and reagent types in simple chemical language.
- Connect 1. fission with 2. nu and e+ using equations, observations, or trends where needed.
- Answer a short Federal Board question with the correct terms and a clear reason.
Examples
- Cl-Cl light
- C-Cl in SN1 named
- Ions in polar solvents
FISSION
UV on Cl2: radicals (named initiation). Heterolytic in SN1 (later) makes a carbocation. Do not write harmful radical-chain processes. Electrophile seeks e- pair; nucleophile donates e- pair — labels for organic mechanisms.
Nu AND E+
OH- attacks carbon of C-Br (later SN2 idea). Alkene C=C attacks Br-Br (electrophilic addition). Acid H+ is an electrophile. Curved arrows show electron movement in mechanism sketches.
Recommended for Class 11
Full school-level explanation
Homolytic fission: each atom takes one electron, radicals (odd e-) named. Heterolytic: both electrons stay with one atom, ions (carbocation / carbanion named). Reagents: electrophile wants electrons (Br-d+ in Br2/alkene school). Nucleophile has a pair to give (OH-, NH3, CN- named as school examples). Free-radical named in methane + Cl2 (light) as a type, not a chain-weapon story. Meaning: the arrow in a mechanism follows the pair (school curly arrows if asked). Homolytic: one e each — radicals; heterolytic: both e to one atom — ion pair. Convert between formula types before naming; longest chain and lowest locants decide IUPAC marks.
Split, then who attacks:
WHAT — BOND FISSION AND REAGENT TYPES
Homolytic fission: each atom takes one electron, radicals (odd e-) named. Heterolytic: both electrons stay with one atom, ions (carbocation / carbanion named). Reagents: electrophile wants electrons (Br-d+ in Br2/alkene school). Nucleophile has a pair to give (OH-, NH3, CN- named as school examples). Free-radical named in methane + Cl2 (light) as a type, not a chain-weapon story. Meaning: the arrow in a mechanism follows the pair (school curly arrows if asked). Homolytic: one e each — radicals; heterolytic: both e to one atom — ion pair. Convert between formula types before naming; longest chain and lowest locants decide IUPAC marks.
WHY — Why this topic matters
BOND FISSION AND REAGENT TYPES is an independent FBISE learning unit because students must use its definitions, conditions, equations, or trends separately in explanations and calculations.
HOW — How it works
FISSION: UV on Cl2: radicals (named initiation). Heterolytic in SN1 (later) makes a carbocation. Do not write harmful radical-chain processes. Electrophile seeks e- pair; nucleophile donates e- pair — labels for organic mechanisms. Examples: Cl-Cl light; C-Cl in SN1 named; Ions in polar solvents. Nu AND E+: OH- attacks carbon of C-Br (later SN2 idea). Alkene C=C attacks Br-Br (electrophilic addition). Acid H+ is an electrophile. Curved arrows show electron movement in mechanism sketches. Examples: OH- nucleophile; Br2 electrophile with alkenes; NH3 nucleophile named. Exam pair: nucleophile: electron-pair donor (OH-) electrophile: electron-pair acceptor (H+, Br2 with alkenes) homolytic fission makes radicals
FISSION
UV on Cl2: radicals (named initiation). Heterolytic in SN1 (later) makes a carbocation. Do not write harmful radical-chain processes. Electrophile seeks e- pair; nucleophile donates e- pair — labels for organic mechanisms.
Remember
- one e- each vs pair stays
Examples
- Cl-Cl light
- C-Cl in SN1 named
- Ions in polar solvents
Nu AND E+
OH- attacks carbon of C-Br (later SN2 idea). Alkene C=C attacks Br-Br (electrophilic addition). Acid H+ is an electrophile. Curved arrows show electron movement in mechanism sketches.
Remember
- pair to empty / d+
Examples
- OH- nucleophile
- Br2 electrophile with alkenes
- NH3 nucleophile named
Remember
- homo = radicals
- hetero = ions
- Nu has a pair, E+ wants a pair
- Nu vs E+
- types only
- one e- each vs pair stays
- pair to empty / d+
- homo = radicals
How the ideas connect
Exam pair: nucleophile: electron-pair donor (OH-) electrophile: electron-pair acceptor (H+, Br2 with alkenes) homolytic fission makes radicals
Deeper understanding
Go beyond memorising Bond Fission and Reagent Types. Connect the definition to reasons, relationships, exceptions, and exam wording.
How the ideas connect
Exam pair: nucleophile: electron-pair donor (OH-) electrophile: electron-pair acceptor (H+, Br2 with alkenes) homolytic fission makes radicals
Common mistakes
Exam focus
Core Idea
1. FISSION
2. Nu AND E+
Exam Example
Exam focus
Quick revision
- homo = radicals
- hetero = ions
- Nu has a pair, E+ wants a pair
- Nu vs E+
- BOND FISSION AND REAGENT TYPES: Homolytic fission: each atom takes one electron, radicals (odd e-) named.
- 1. FISSION: UV on Cl2: radicals (named initiation).
School types. No radical-weapon or illicit mechanism sheets.
For long answers on Bond Fission and Reagent Types: define clearly → explain the main parts → give one example → state one exam caution.
Exam Focus
Exam Focus
Important points
- homo = radicals
- hetero = ions
- Nu has a pair, E+ wants a pair
- Nu vs E+
Important formulas
- homo = radicals
- hetero = ions
- Nu has a pair, E+ wants a pair
Common exam traps
- Do not confuse 1. FISSION with 2. Nu AND E+; state the difference before giving an example.
- Writing only “homo = radicals” is not enough. Explain what it means in a complete sentence.
Long question structure
Definition → key parts → example → exam caution
Common Mistakes
Common Mistakes
- Mistake
Do not confuse 1. FISSION with 2. Nu AND E+; state the difference before giving an example.
- Mistake
Writing only “homo = radicals” is not enough. Explain what it means in a complete sentence.
- Mistake
School types. No radical-weapon or illicit mechanism sheets.
- Mistake
School types. No radical-weapon or illicit mechanism sheets.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
homo = radicals
hetero = ions
Nu has a pair, E+ wants a pair
Nu vs E+
Homolytic fission: each atom takes one electron, radicals (odd e-) named. Heterolytic: both electrons stay with one atom, ions (carbocation / carbanion named).
homo = radicals
- Definition
- Homolytic fission: each atom takes one electron, radicals (odd e-) named. Heterolytic: both electrons stay with one atom, ions (carbocation / carbanion named).
- Formula
- homo = radicals
- Example
- Cl-Cl light
- Critical warning
- Do not confuse 1. FISSION with 2. Nu AND E+; state the difference before giving an example.
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Exam Practice
Define
Q1. Define Bond Fission and Reagent Types.
Explain
Q2. Explain: FISSION.
Example
Q3. Give one clear example of Bond Fission and Reagent Types and say why it fits.
Mistake
Q4. State one common mistake students make about Bond Fission and Reagent Types.
Exam note
Q5. Write a short exam note on Bond Fission and Reagent Types: definition, two points, one example.
Sources & References
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.