1.4 Chemical Bonding

• Why atoms form bonds
• Ionic bonding
• Covalent bonding
• Metallic bonding
• Relationship between bond type, structure and physical properties

• illustrate bond types in elements, molecules and compounds
• investigate the relationship between bond types and physical properties
• relate bond types and resultant structures to the uses of substances
• appreciate the uses of different substances based on their bond types and structures

“Why does salt dissolve and melt at high temperature while wax melts in your hand?”

The titles are open to everyone. Reading a lesson needs an account — sign in or create one.

1. Types of bonding
   40 min · 2 practice tasks · quiz
   Three ways atoms achieve a full outer shell, and how to tell which applies.
2. Structure and properties
   40 min · 2 practice tasks · quiz
   Why bonding decides melting point, solubility and whether something conducts.
3. Why atoms form bonds
   40 min · 1 practice tasks · quiz
   Atoms bond to reach a full outer shell, matching the nearest noble gas, and that lowers their energy.
4. Ionic bonding: electron transfer
   40 min · 1 practice tasks · quiz
   A metal transfers outer electrons to a non-metal; the ions then attract.
5. Ionic charges and formulae
   40 min · 1 practice tasks · quiz
   Group number gives the ion charge; formulae balance so the total charge is zero.
6. Dot-and-cross diagram for NaCl
   40 min · 1 practice tasks · quiz
   Draw sodium transferring its outer electron to chlorine, then show Na+ and Cl- with full shells.
7. Dot-and-cross for MgO and CaCl2
   40 min · 1 practice tasks · quiz
   Transfer two electrons for MgO; use two chlorines for CaCl2 so every atom is full.
8. The giant ionic lattice
   40 min · 1 practice tasks · quiz
   Ionic compounds are 3-D lattices of ions, not molecules; NaCl is a 1:1 ratio.
9. Properties of ionic compounds
   40 min · 1 practice tasks · quiz
   High melting point, brittle, often water-soluble, conduct only when molten or dissolved.
10. Kenyan salt and Magadi soda
    40 min · 1 practice tasks · quiz
    Coastal chumvi and Magadi soda ash are giant ionic solids whose uses follow from that structure.
11. Covalent bonding: sharing pairs
    40 min · 1 practice tasks · quiz
    Two non-metals share electron pairs so both can count a full outer shell.
12. Dot-and-cross for H2, Cl2 and HCl
    40 min · 1 practice tasks · quiz
    Draw single covalent bonds in the three classic diatomic molecules.
13. Water, ammonia and methane
    40 min · 1 practice tasks · quiz
    Oxygen forms two bonds, nitrogen three, carbon four - the number needed to fill.
14. Double and triple covalent bonds
    40 min · 1 practice tasks · quiz
    Oxygen shares two pairs, nitrogen three; carbon dioxide has two double bonds.
15. Simple molecular structures
    40 min · 1 practice tasks · quiz
    Covalent molecules are separate units held to each other only by weak intermolecular forces.
16. Properties of simple molecular substances
    40 min · 1 practice tasks · quiz
    Low melting and boiling points, usually insoluble in water, do not conduct - all from weak intermolecular forces.
17. Diamond: a giant covalent network
    40 min · 1 practice tasks · quiz
    Each carbon bonded to four others in 3-D; that is why diamond is hard, high-melting and an insulator.
18. Graphite: layers that slide and conduct
    40 min · 1 practice tasks · quiz
    Each carbon bonds to three others; leftover electrons conduct, and weak forces let layers slide - pencils and electrodes.
19. Sand and silica: another giant covalent solid
    40 min · 1 practice tasks · quiz
    SiO2 is a network, not a CO2-style molecule; that is why sand survives a Bunsen flame and makes glass and concrete.
20. Metallic bonding: a sea of electrons
    40 min · 1 practice tasks · quiz
    Metal atoms pack as positive ions in a delocalised electron sea; that is the metallic bond.
21. Metal properties from the electron sea
    40 min · 1 practice tasks · quiz
    Delocalised electrons explain conduction and heat; sliding layers explain malleability and ductility.
22. Conductivity across four structures
    40 min · 1 practice tasks · quiz
    A substance conducts only if charged particles can move: electrons in metals and graphite, ions when ionic compounds melt or dissolve.
23. Investigating unknown solids
    40 min · 1 practice tasks · quiz
    Use melting behaviour, solubility and conductivity to classify a substance as ionic, simple molecular, giant covalent or metallic.
24. Choosing materials from structure
    40 min · 1 practice tasks · quiz
    Uses of salt, graphite, diamond, copper, aluminium, sand and plastics follow from bonding and structure.