Chemical Bonding and Reactions

5 min

Master ionic/covalent bonds, balancing, and redox reactions for competitive exams.

The Golden Rule

Atoms achieve stability by transferring or sharing electrons to complete their octet. Chemical reactions strictly follow the law of conservation of mass during balancing.

Why This Matters

Direct questions on bond types like NaCl and H2O appear in all SSC & Railway exams.
Balancing equations is essential for solving numerical problems in stoichiometry.
Redox reactions form the core of electrochemistry and everyday oxidation questions.

Memory Hooks

LEO says GER: Loss of Electrons is Oxidation, Gain of Electrons is Reduction.
IONic bonds: GIVE and TAKE (metal + non-metal transfer).
COvalent bonds: CO-OWNERSHIP (non-metal sharing).

Bond Types Comparison

Bond Property	Ionic Bond	Covalent Bond
Particle Type	Metal & Non-metal	Non-metals only
Electron Action	Complete Transfer	Mutual Sharing
Melting Point	High	Low
Example	NaCl	H2O

Reaction Types Visual

Combination

(A + B -> AB)

A + B -> AB

Burning of magnesium ribbon forms magnesium oxide.

Decomposition

(AB -> A + B)

AB -> A + B

Heating calcium carbonate gives calcium oxide and CO2.

Displacement

(A + BC -> AC + B)

A + BC -> AC + B

Iron displaces copper from copper sulfate solution.

Redox

(Electron Transfer)

Electron Transfer

Zinc reducing copper ions in solution.

Common Exam Traps

Covalent compounds conduct electricityIonic compounds conduct in molten state

Covalent molecules lack free ions, so they are poor conductors of electricity in water.

Oxidation means only adding oxygenOxidation is also loss of electrons

Modern definition of oxidation includes removal of hydrogen or loss of electrons, not just adding oxygen.

Subscripts can be changed to balanceOnly coefficients can be changed

Changing chemical formulas (subscripts) alters the substance itself. Always use coefficients.

Exam Practice Quiz

Q1.Which of the following compounds contains an ionic bond?

Q2.In the reaction Zn + CuSO4 -> ZnSO4 + Cu, what type of reaction is taking place?

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