A metal holds together. Its electrons can move.
A copper wire bends without falling into separate atoms, and it carries an electric current. Both observations lead to the same picture: a regular array of positive ion cores, held together by electrons shared throughout the metal.
01Meet the lattice and its shared electrons
The silver spheres are positive ion cores: a nucleus with its tightly bound inner electrons. Some outer electrons are delocalised—they do not belong to one particular atom. The attraction between these negative electrons and the positive cores is metallic bonding. The fine blue links below make this collective attraction visible; they are not individual, permanent bonds.
Model key: a schematic monovalent metal, 45 cores and 45 delocalised-electron markers. Core sizes, electron paths, drift speed and attraction links are teaching symbols, not atomic-scale trajectories or a quantitative conductivity calculation. The simple lattice does not specify copper’s actual crystal structure.
02Read the properties from the model
Electrical conduction
A field biases the motion of mobile electrons. There is charge transport without moving the whole solid. Reversing the field reverses both current and electron drift.
Malleability
Metal can change shape because layers can rearrange while sharing mobile electrons. The attraction is spread throughout the solid, rather than tied to a single pair of atoms.
Attraction is mutual
Cores attract the electrons; electrons attract the cores. The stable spacing also depends on repulsive and quantum effects. Attraction alone would not explain why matter has a finite size.
Check: if the current points right, which way do the electrons drift?
Left. Electrons carry negative charge, while conventional current uses the positive-charge direction. The local motion and much smaller net drift are different ideas.