Neco Chemistry Exam 2025/2026: Full List Of Highly Repeated Topics & Past Questions

The NECO Chemistry Exam is a core subject for science students preparing for university admission into medical, engineering, and science-related courses. One of the smartest ways to pass this exam is by focusing on highly repeated topics and practicing real past questions. This blog provides a complete list of frequently tested topics and sample questions to help you prepare efficiently.

Full List of Highly Repeated Topics in NECO Chemistry Exam

1. Atomic Structure and Periodic Table

• Structure of atoms

• Isotopes

• Electron configuration

• Periodic trends: electronegativity, ionization energy, etc.

Sample Question:
State the number of protons, electrons, and neutrons in an atom of ₁₁²³Na.

2. Chemical Bonding

• Ionic, covalent, and metallic bonds

• Properties of compounds formed by each type of bond

• Hydrogen bonding and Van der Waals forces

Sample Question:
Differentiate between ionic and covalent bonds with examples.

3. Stoichiometry and Chemical Calculations

• Mole concept

• Empirical and molecular formula

• Reacting mass calculations

• Percentage composition and yield

Sample Question:
Calculate the mass of NaOH required to neutralize 25 cm³ of 0.1 M HCl.

4. States of Matter

• Properties of solids, liquids, and gases

• Gas laws: Boyle’s, Charles’s, and Ideal Gas Equation

• Kinetic theory of matter

Sample Question:
State Boyle’s law and give its mathematical expression.

5. Energy Changes in Reactions

• Endothermic and exothermic reactions

• Enthalpy change

• Heat of combustion and neutralization

Sample Question:
Distinguish between exothermic and endothermic reactions with examples.

6. Acids, Bases, and Salts

• Properties of acids and bases

• pH scale and indicators

• Neutralization reactions

• Preparation of salts

Sample Question:
Describe how to prepare a pure sample of copper(II) sulfate crystals in the laboratory.

7. Chemical Equilibrium

• Reversible and irreversible reactions

• Le Chatelier’s Principle

• Factors affecting equilibrium (temperature, pressure, concentration)

Sample Question:
Explain what happens to the equilibrium position when temperature increases in an endothermic reaction.

8. Redox Reactions and Electrolysis

• Oxidation and reduction in terms of electron transfer

• Electrochemical cells

• Electrolysis of molten and aqueous compounds

Sample Question:
Define oxidation and reduction using electron transfer theory.

9. Rates of Reaction

• Factors affecting rate: temperature, concentration, surface area, catalyst

• Collision theory

Sample Question:
List four factors that affect the rate of chemical reactions.

10. Organic Chemistry

• Hydrocarbons: alkanes, alkenes, alkynes

• Functional groups: alcohols, carboxylic acids

• Homologous series

• Isomerism

Sample Question:
Write the structural formula of but-2-ene and name the type of isomerism it exhibits.

11. Environmental Chemistry

• Air pollution and greenhouse gases

• Water treatment

• Effects of acid rain

Sample Question:
Explain how water can be purified for domestic use.

12. Metals and Their Compounds

• Extraction of metals (e.g., iron, aluminium)

• Alloys and their uses

• Reactivity series

Sample Question:
List the steps involved in the extraction of iron from its ore.

13. Non-Metals and Their Compounds

• Properties and uses of non-metals (e.g., chlorine, sulphur, oxygen)

• Preparation of gases in the lab

Sample Question:
Describe the laboratory preparation of oxygen gas.

Sample NECO Chemistry Objective Questions

1. Which of the following gases is monatomic?
   A. Oxygen
   B. Nitrogen
   C. Neon
   D. Chlorine
   Answer: C

2. The atomic number of an element is 17. How many electrons are in its outermost shell?
   A. 5
   B. 7
   C. 3
   D. 2
   Answer: B

3. The IUPAC name of CH₃CH₂CH₃ is:
   A. Methane
   B. Ethane
   C. Propane
   D. Butane
   Answer: C

4. Which of the following is a base?
   A. HCl
   B. NaOH
   C. HNO₃
   D. H₂SO₄
   Answer: B

5. What is the oxidation number of sulfur in H₂SO₄?
   A. +4
   B. +6
   C. -2
   D. +2
   Answer: B

How to Pass NECO Chemistry Easily

• Focus on highly repeated topics above

• Practice past questions consistently

• Create summary notes and diagrams

• Watch YouTube tutorials for practicals

• Use mnemonics and flashcards for formulas

Frequently Asked Questions (FAQs)

Q1: How many papers are in NECO Chemistry?

There are two papers:

• Paper I: Objective (Multiple Choice)

• Paper II: Theory and Practical (Structured and Essay)

Q2: What is the most repeated topic in NECO Chemistry?

Topics like stoichiometry, organic chemistry, and electrolysis are highly repeated every year.

Q3: Are there practicals in NECO Chemistry?

Yes. Students are tested on practical skills including titration, identification of gases, and observation of chemical changes.

Q4: What is the best textbook to use for NECO Chemistry?

Recommended textbooks include:

• New School Chemistry by Osei Yaw Ababio

• Chemistry for Senior Secondary Schools by Ladi A. Buraimoh

Q5: Can NECO Chemistry questions be predicted?

While questions cannot be 100% predicted, many topics are repeated regularly. That’s why studying the ones in this guide is crucial.

Conclusion

To excel in the NECO Chemistry Exam 2025/2026, focus on the high-yield topics, solve past questions, and understand the concepts, not just cram them. Let this guide be your roadmap to achieving an A1.