How to Pass NECO Chemistry in 2027: A Families Approach

If you try to learn Chemistry as a long list of facts, it will feel endless. If you learn it as families (groups of elements, series of compounds, types of reaction), it shrinks to a manageable number of patterns. This guide organises NECO Chemistry for the 2027 cycle around those families. For a plan built mainly around the mole concept and the practical, see how to pass WAEC Chemistry; the two guides complement each other.

First, check the current NECO syllabus and paper format on neco.gov.ng. The ExamPadi subject outline lists the periodic table, chemical bonding, stoichiometry, acids, bases and salts, electrolysis, organic chemistry, hydrocarbons, polymers, industrial chemistry and environmental chemistry.

Family 1: elements and the periodic table

Instead of learning each element, learn the groups.

Learn the trends across a period (atomic radius, ionisation energy, metallic to non-metallic character) and be ready to explain them using electron arrangement.

Family 2: types of bonding

Link bonding to properties, because that is how questions are usually asked.

• Ionic: transfer of electrons; high melting points; conducts when molten or dissolved.
• Covalent (simple molecules): sharing of electrons; low melting points; usually do not conduct.
• Covalent (giant structures): diamond and silicon dioxide have very high melting points; graphite conducts.
• Metallic: sea of electrons; malleable and conducts.

Practise drawing dot-and-cross diagrams for simple compounds.

Family 3: acids, bases and salts

Organise salt preparation into a decision path:

1. Is the salt soluble? If yes, use acid plus metal, base or carbonate, then crystallise.
2. Is it insoluble? Use precipitation by mixing two solutions, then filter and dry.
3. If the salt is a sodium, potassium or ammonium salt (made from an alkali), use titration to find the exact amount of acid needed, then crystallise.

Learn the indicators and their colours, the pH scale and the difference between strong and weak acids.

Family 4: reaction types

Treat reactions as families too: combination, decomposition, displacement, neutralisation, precipitation, redox and combustion. For redox, remember the pairing: oxidation is loss of electrons and reduction is gain.

Family 5: electrolysis

Electrolysis is an area where good preparation pays off.

1. Identify the ions present (from the compound and from water).
2. Decide what goes to the cathode (positive ions, which gain electrons) and the anode (negative ions, which lose electrons).
3. Write the half-equations.
4. Note any changes in the electrolyte.

Compare the electrolysis of molten sodium chloride with that of its solution, and learn applications such as electroplating and purification of metals.

Family 6: organic chemistry

Organise by homologous series.

Learn how polymers form (addition and condensation), with examples such as polythene and nylon. Name compounds by counting carbons and identifying the functional group.

Calculations: the mole method

An original example to practise:

What volume of hydrogen at s.t.p. is produced when 1.2 g of magnesium reacts with excess dilute hydrochloric acid? (Mg = 24; molar volume = 22.4 dm³.)

• Mg + 2HCl → MgCl₂ + H₂
• Moles of Mg = 1.2 / 24 = 0.05 mol
• The ratio Mg : H₂ is 1 : 1, so 0.05 mol of H₂ forms
• Volume = 0.05 × 22.4 = 1.12 dm³

A second calculation type: concentration

Concentration questions follow the same mole logic. Here is an original example.

How many grams of anhydrous sodium carbonate (Na₂CO₃; Na = 23, C = 12, O = 16) are needed to make 500 cm³ of a 0.1 mol/dm³ solution?

• Moles = concentration × volume in dm³ = 0.1 × 0.5 = 0.05 mol
• Molar mass of Na₂CO₃ = 46 + 12 + 48 = 106 g/mol
• Mass = 0.05 × 106 = 5.3 g

Convert cm³ to dm³ by dividing by 1000, and write the unit at each stage. Titration questions combine this with a balanced equation, so practise both together.

Industrial and environmental chemistry

Learn the raw materials, conditions and uses for the main industrial processes in the syllabus, plus the causes, effects and control of pollution. A cause-effect-control table is the quickest way to revise.

Study plan by family

See NECO Chemistry topics to focus on and the WAEC chemistry practical tips for practical-style questions.

Mistakes to avoid

• Writing unbalanced equations.
• Mixing up the cathode and the anode.
• Forgetting units in calculations.
• Learning facts without understanding the trends behind them.
• Chasing "expo", which cannot help you with a calculation or a half-equation.

Practise it

ExamPadi's free NECO Chemistry questions offer objective practice with a timed CBT mode on Android, iOS, web and Windows. Use them to identify which family is weakest, then return to your notes for that family.

Begin at NECO Chemistry practice.