How can a metal conduct and bend?
You will be able to: Use mobile electrons and positive metal cores to explain two metallic properties.
How can a metal conduct and bend?
A piece of copper wire can carry current and be bent into a new shape. Its bonding model must account for both electron mobility and cohesion after atoms rearrange.
A useful starting point: Why is a salt crystal an extended 3D structure? →
Words and symbols before equations
- Positive metal core
- Nucleus plus tightly held electrons, excluding delocalized valence electrons.
- Electron sea
- A model of valence electron density extending across the metal.
- Malleability
- Ability to deform under compression without immediately fracturing.
What this picture assumes
Schematic eight-site block. + marks positive metal cores; delocalized electrons are indicated in the 2D background, not individual calculated trajectories. Alloy spheres represent atoms/sites, with sizes chosen only to distinguish guest placement.
Read the picture in three steps
- Read the species and labels first. A Lewis line represents two electrons; a spatial stick indicates connectivity. Use the stated quantities and units for numerical comparisons.
- Pure: 8 host cores. Guest fraction: 0% of atoms.
- Check what the picture assumes below. Use the Explore task to predict one change before moving a control.
Connect the picture to the chemistry
In a metallic model, delocalized electrons are attracted to many positive cores. The whole sample remains electrically neutral, even though its components are represented with opposite charges.
An electric field can produce a small directed drift of the electrons. The cores do not have to travel through the wire for current to flow.
When layers rearrange, electron density can continue binding neighboring cores. This helps explain why many metals deform more readily than ionic crystals. Real hardness and ductility also depend on defects, grain structure and composition.
A worked example, step by step
A model has four +1 cores and four delocalized electrons. Explain neutrality and conduction.
- The model core charge totals +4e.
- Four electrons contribute −4e; the overall charge is zero.
- The delocalized electrons can move through the structure under an applied field.
- Conduction does not require the whole material to be negatively charged or its positive cores to flow like a liquid.
“Electron sea” is a model of distributed electron density, not a literal liquid between tiny rigid balls.
Does a conducting metal need a net negative charge?
Compare with an explanation
No. A neutral metal can have mobile electrons and matching positive core charge.
Predict. Change one thing. Explain.
Compare the pure-metal diagram with the alloy options. For the pure metal, identify which particles represent the mobile carriers and which represent cores.
On narrow screens, swipe or scroll diagrams sideways to read all labels.
Pure: 8 host cores. Guest fraction: 0% of atoms.
Schematic eight-site block. + marks positive metal cores; delocalized electrons are indicated in the 2D background, not individual calculated trajectories. Alloy spheres represent atoms/sites, with sizes chosen only to distinguish guest placement.
Explain what you noticed: Answer the investigation prompt above. State one observation and explain it using electron accounting, electrostatic interactions or spatial geometry. Identify what the representation cannot tell you.
Apply the idea to a fresh problem Practice →Show what you understand.
Two original questions are a starting check, not proof of mastery. Explain your choice before revealing the answer.
Original written challenge
4 points · self-check · not an official AP questionUse a particle model to explain why neutral aluminum can conduct and be shaped. Include charges, mobility, bonding after rearrangement, and a model limitation.
This response is not submitted or saved. Copy it before leaving.
Compare with the answer and four-point rubric
- 1 point: Represent positive cores with compensating delocalized negative charge.
- 1 point: Electrons can drift through the sample.
- 1 point: Electron–core attractions can persist as cores rearrange.
- 1 point: The simple model alone does not quantitatively predict every metal’s hardness or ductility.
Accept equivalent correct methods and explanations. This is a Refresh Kid teaching rubric, not an official AP scoring guideline.
Retrieve it before you reveal it.
RECALL 1What is delocalized?
Valence electron density extends across many cores.
RECALL 2Why can a neutral sample conduct?
Carrier mobility does not require net sample charge.
RECALL 3What else affects mechanical properties?
Defects, grain structure, composition and temperature, among other factors.
Revisit these tomorrow and a week later. Try a fresh problem and explain why the method applies.
How can a metal conduct and bend?
- Neutrality: positive core charge balances delocalized electron charge.
- Mobile electrons can carry current in a solid.
Remember: “Electron sea” is a model of distributed electron density, not a literal liquid between tiny rigid balls.
Conditions: Schematic eight-site block. + marks positive metal cores; delocalized electrons are indicated in the 2D background, not individual calculated trajectories. Alloy spheres represent atoms/sites, with sizes chosen only to distinguish guest placement.
Refresh Kid · AP Chemistry Unit 2 · Objectives 2.4.A · Review edition
Framework, scope and review status
Mapped to College Board CED, Topic 2.4, objectives 2.4.A. CED effective Fall 2024, current official file checked September 16, 2026, together with the published clarifications. This is Unit 2: Compound Structure and Properties, Topics 2.1–2.7. The focused lesson breakdown is Refresh Kid’s editorial sequence. Models and original practice are teaching materials, not official AP questions. Numerical potential curves, ion comparisons and orbital-alignment indices state their approximations. Five- and six-domain shapes are included; d-orbital hybridization and molecular-orbital diagrams are not required here. GitHub’s 3D website examples, including the Three.js Mars camera-control example, informed the use of rotatable scenes. Our scientific geometry and viewer code are original; no repository artwork or tutorial code was copied. The self-hosted Three.js library retains its MIT license. Camera rotation does not alter chemistry. See also the official clarifications.
Implementation and automated checks are separate from independent teacher review and observation of students. Both human review stages remain pending. This is a review edition, not a certified or validated assessment.
Optional further resource: College Board’s released questions and scoring guides. Papers can combine units; this link is an archive, not an assignment of every question to this lesson.
Our learn, explore, practice and recall sequence is informed by the IES learning guide. The exact Refresh Kid implementation has not been evaluated for learning effectiveness.
Want to work through this with a tutor?
Bring your question about How can a metal conduct and bend? Your explanation and answers remain free to access.