SSC CGL - Detailed Guide 2025

Self-Paced Course

Chemical Bonding and Reactions

Reference: Lucent GK, NCERT Class 6–12

Feature	Description
Definition	Electrostatic force of attraction between oppositely charged ions
Occurs Between	Metal (loses e⁻) and Non-metal (gains e⁻)
Electron Transfer	Complete transfer from metal to non-metal
Properties	High melting & boiling point, soluble in water, conduct electricity in solution
Example	NaCl (Na⁺ + Cl⁻), CaCl₂

Metal atoms lose electrons to form cations, non-metals gain to form anions.

Feature	Description
Definition	Sharing of electrons between atoms
Occurs Between	Non-metal and non-metal
Electron Transfer	No transfer; shared pairs of electrons form bonds
Properties	Low melting & boiling point, poor conductor, often insoluble in water
Example	H₂, O₂, CO₂, CH₄

Can be single (H₂), double (O₂), or triple (N₂) covalent bonds.

A symbolic representation of a chemical reaction showing reactants & products
Example: 2H₂ + O₂ → 2H₂O
- Reactants: Substances that react
- Products: Substances formed

Step	Description
1. Write skeleton equation	Unbalanced equation with formulas
2. Count atoms	Compare number of atoms on both sides
3. Balance using coefficients	Adjust numbers (not subscripts) to equal atoms
4. Double check	Recount to ensure balance is correct

Follows Law of Conservation of Mass: mass of reactants = mass of products.

Type	Description	General Form	Example
Combination	Two or more substances combine to form one product	A + B → AB	H₂ + Cl₂ → 2HCl
Decomposition	One compound breaks into two or more simpler substances	AB → A + B	2H₂O₂ → 2H₂O + O₂
Displacement	One element displaces another in a compound	A + BC → AC + B	Zn + CuSO₄ → ZnSO₄ + Cu
Double Displacement (exchange reaction)	Two compounds exchange ions to form two new compounds	AB + CD → AD + CB	NaCl + AgNO₃ → NaNO₃ + AgCl↓

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