Question

3. What are bonds in metals like?

Answer 1

Metallic bonds are the type of bonding that holds metal atoms together. In simplest terms: metal atoms donate their valence electrons into a shared, delocalized "sea" of electrons that flows throughout a lattice of positive metal ions. Key points:

- Electron-sea picture: atoms become positive ions fixed in a lattice and the freed valence electrons move relatively freely through the structure.
- Band-theory view (quantum): atomic orbitals overlap to form broad energy bands; partially filled conduction bands allow electrons to move under an applied field.
- Non‑directional: the bond is not between specific atom pairs, so electrons bind the structure collectively rather than along fixed lines.

How this gives metals their properties:
- Electrical conductivity: mobile electrons carry electric current.
- Thermal conductivity: moving electrons also transport heat efficiently.
- Malleability and ductility: layers of ions can slide past each other without breaking bonds because the electron sea re‑arranges to keep ions attracted.
- Luster (shine): delocalized electrons absorb and re‑emit visible light.
- Generally high melting/boiling points and variable strength: depends on valence electron count, atomic size, crystal structure and involvement of d‑electrons (transition metals are often stronger).

Contrast with other bonds:
- Unlike ionic bonds (electrostatic attraction between oppositely charged ions) metallic bonds are delocalized and non‑directional.
- Unlike covalent bonds, electrons are not shared between specific atom pairs but are spread across the whole metal.

If you want, I can show band diagrams, compare specific metals (e.g., Na vs. Fe), or explain how alloying changes metallic bonding.