Chemical Bonding
Infer bonding from electron behavior and observable properties.
Chemical Bonding
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Connect electron behavior to structure, then connect structure to properties
Ionic bonding: electron transfer produces oppositely charged ions held in a lattice. Covalent bonding: atoms share electron pairs; the result may be separate molecules or a continuous network. Metallic bonding: delocalized electrons move through a lattice of metal particles.
Need the quick foundation?
Valence electrons are the outer electrons involved in bonding. Bond type is a model for what happens to these electrons. Observable properties—conductivity, melting point, brittleness, malleability, and solubility—provide evidence for the model.
Do not classify from one clue alone. For example, both ionic and network covalent solids can have high melting points.
Use composition
Metal + nonmetal often suggests ionic; nonmetal + nonmetal often suggests covalent. This predicts the likely bond type but is not the only evidence.
Use properties
Ask what particles carry charge, whether they can move, and how strongly the particles are held together.
Read every property as evidence about particles
Problem: A brittle high-melting solid conducts electricity when molten but not when solid.
Recognize each clue:
- High melting point: strong attractions hold charged particles in a rigid lattice, so much energy is needed to separate them.
- Brittle: when lattice layers shift, ions with the same charge can line up, repel, and split the crystal.
- No conduction as a solid: ions are charged, but they are locked in fixed positions.
- Conduction when molten: melting frees the ions to move and carry electric charge.
Do it fast: All four clues fit an ionic compound. Do not rely on “high melting point” alone; use the entire pattern.
Why it works
A formula gives an initial prediction, while physical properties reveal whether the material actually contains fixed ions, mobile electrons, or separate molecules.
Five forms you should recognize
Sodium loses one valence electron to form Na+; chlorine gains it to form Cl−. Opposite charges attract throughout a crystal lattice.
Solid salt already contains charged ions, but they are locked in place. Melting frees the ions to move and carry charge.
Each O–H bond is polar. Because H₂O is bent, the two bond dipoles do not cancel, leaving a net molecular dipole.
Its C=O bonds are polar, but the molecule is linear and symmetric. Equal, opposite dipoles cancel.
Boiling separates molecules rather than breaking their internal covalent bonds. Stronger intermolecular attractions therefore require a higher temperature.
Check before you commit
- Calling every polar bond ionic
- Saying electrons are shared in ionic bonding
- Expecting solid salts to conduct
- Confusing bonds with intermolecular forces
- Counting all electrons as valence electrons
- Using one property as absolute proof
Do you need the lesson-or just practice?
One original question in each form recommends your next step. It does not yet verify mastery.
Work at the level you need.
Foundations
Build the core procedure with immediate explanations.
Core Practice
Use mixed forms with less scaffolding.
UPCAT-Style Transfer
Apply the competency in unfamiliar representations.
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Chemical Bonding FAQ
Why does solid NaCl not conduct if it contains charged ions?
Its ions are locked in the crystal lattice. Charge can flow only when the ions become mobile, such as after melting or dissolving in water.
Why are many ionic solids brittle?
A force can shift lattice layers so that like charges face one another. Their repulsion can split the crystal.
Are all metal–nonmetal compounds perfectly ionic?
Bonding exists on a continuum, but introductory classification uses dominant character.
Why do metals bend without shattering?
Metallic bonding is nondirectional, allowing layers to shift while attraction through delocalized electrons remains.
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