Chemical bonds: WAEC Chemistry Past Questions and Answers

What the WAEC syllabus covers in Chemical bonds

Our summary: How atoms join through ionic, covalent, dative and metallic bonds, the forces between molecules, and the shapes molecules take.

• Interatomic bonding (Meaning of chemical bonding. Lewis dot structure for simple ionic and covalent compounds.)
• Formation of ionic bonds and compounds (Formation of stable compounds from ions. Factors influencing formation: ionization energy; electron affinity and electronegativity difference.)
• Properties of ionic compounds (Solubility in polar and non-polar solvents, electrical conductivity, hardness and melting point.)
• Naming of ionic compounds (IUPAC system for simple ionic compounds.)
• Formation of covalent bonds and compounds (Factors influencing covalent bond formation. Electron affinity, ionization energy, atomic size and electronegativity.)
• Properties of covalent compounds (Solubility in polar and non-polar solvents, melting point, boiling point and electrical conductivity.)
• Coordinate (dative) covalent bonding (Formation and difference between pure covalent and coordinate (dative) covalent bonds.)
• Shapes of molecular compounds (Linear, planar, tetrahedral and shapes for some compounds e.g. BeCl₂, BF₃, CH₄, NH₃, CO₂.)
• Metallic bonding
• Metallic bonding: factors influencing its formation (Factors should include: atomic radius, ionization energy and number of valence electrons. Types of specific packing not required.)
• Metallic bonding: properties of metals (Typical properties including heat and electrical conductivity, malleability, lustre, ductility, sonority and hardness.)
• Intermolecular bonding (Relative physical properties of polar and non-polar compounds.)
• Intermolecular forces in covalent compounds (Description of formation and nature should be treated. Dipole-dipole, induced dipole-dipole, induced dipole-induced dipole forces should be treated under van der Waals' forces.)
• Hydrogen bonding
• van der Waals forces (Variation of the melting points and boiling points of noble gases, halogens and alkanes in the homologous series explained in terms of van der Waals' forces; and variation in the boiling points of H₂O and H₂S explained using hydrogen bonding.)
• Comparison of all bond types

Syllabus content © The West African Examinations Council (WASSCE (harmonised West African syllabus)).