ACT SSC Chemistry — Unit 1
Chemical Bonding — Flashcards & Quiz
ACT SSC Chemistry Year 12 Unit 1 covers the four main bonding types (ionic, covalent, metallic, and intermolecular forces) and their influence on physical properties. You need to predict bonding type from electronegativity, explain the structure-property link for each type, and distinguish intramolecular bonds (within molecules) from intermolecular forces (between molecules).
Key Points
- Ionic bonding: electrostatic attraction between positive and negative ions, typically metal + non-metal. Forms 3D lattice.
- Covalent bonding: sharing electron pairs between non-metals. Can be simple molecular or giant covalent (diamond, graphite, SiO₂).
- Metallic bonding: positive metal ions in a "sea" of delocalised electrons. Explains conductivity, malleability, ductility.
- Intermolecular forces (weakest to strongest): dispersion < dipole-dipole < hydrogen bonding. Affect boiling point, solubility.
- Hydrogen bonds require H bonded to N, O, or F — the most electronegative atoms.
- Predict bonding type from electronegativity difference: >1.7 ionic; 0.4–1.7 polar covalent; <0.4 non-polar covalent.
Common Mistakes to Avoid
- Calling intermolecular forces "bonds" — they're weaker than covalent bonds.
- Forgetting that hydrogen bonds require H attached to N, O, or F.
- Mixing up the strength ranking of intermolecular forces (dispersion < dipole-dipole < H-bond).
- Using electronegativity difference without noting there's a continuum between ionic and covalent.
- Claiming all covalent compounds have low melting points — giant covalent (diamond, SiO₂) have very high melting points.
Exam Strategy
BSSS Unit 1 bonding questions ask you to predict bonding type and explain physical properties. Method: (1) identify the elements and their electronegativities, (2) predict bonding type, (3) describe the structure (lattice, molecule, metallic), (4) link to observed properties (melting point, conductivity, solubility).
Sample Flashcards
Q1: Describe ionic bonding and give an example.
Ionic bonding involves the transfer of electrons from a metal to a non-metal, forming oppositely charged ions (cations and anions) held together by electrostatic attraction in a crystal lattice.
Q2: What is a covalent bond?
A covalent bond forms when two non-metal atoms share one or more pairs of valence electrons to achieve a stable electron configuration. Single bonds share one pair; double bonds share two; triple bonds share three.
Q3: Describe metallic bonding.
In metallic bonding, metal cations are arranged in a regular lattice surrounded by a "sea" of delocalised valence electrons. The electrostatic attraction between the positive cations and the mobile electrons holds the structure together.
Sample Quiz Questions
Q1: Ionic compounds can conduct electricity in the solid state.
Answer: FALSE
In the solid state, ions are fixed in the lattice and cannot move. Ionic compounds conduct when molten or dissolved.
Q2: A triple bond is stronger and shorter than a single bond between the same atoms.
Answer: TRUE
Triple bonds share three pairs of electrons, creating stronger attraction and pulling atoms closer together.
Q3: Metals are poor conductors of electricity because their electrons are fixed in place.
Answer: FALSE
Metals are GOOD conductors because their delocalised electrons are free to move throughout the lattice.
Revision Tip
Bonding types and properties pair together — build a Revizi deck matching each bonding type to its structural feature and characteristic property.
Last updated: March 2026 · 3 flashcards · 4 quiz questions