Structure explains what a material does.
In ionic solids, ions cannot move freely, but molten or dissolved ions can carry current. Metals conduct through delocalised electrons and can deform as atomic layers shift. Small covalent molecules usually melt more easily than extended covalent networks. Diamond is a rigid covalent network; graphite has layers and mobile electrons along them.
A pure substance has fixed composition and characteristic properties; a mixture can vary in composition. Homogeneous mixtures are uniform at the observation scale, whereas heterogeneous mixtures have distinguishable regions. Hydrocarbons also differ in bonding: alkenes contain C=C bonds that can undergo addition, while benzene has delocalised bonding.
Mobile charge carriers
Explore the relationship
A counting model, not a conductivity prediction. Solid ionic lattices have negligible ion mobility; molten ions and metallic electrons can move.
Tap or focus a plotted point to read its values.
View plotted data as a table
| Series | Total charged particles / relative units | Mobile charged particles / relative units |
|---|---|---|
| Mobile charged particles / relative units | 0 | 0 |
| Mobile charged particles / relative units | 1.66667 | 0.833333 |
| Mobile charged particles / relative units | 3.33333 | 1.66667 |
| Mobile charged particles / relative units | 5 | 2.5 |
| Mobile charged particles / relative units | 6.66667 | 3.33333 |
| Mobile charged particles / relative units | 8.33333 | 4.16667 |
| Mobile charged particles / relative units | 10 | 5 |
| Mobile charged particles / relative units | 11.6667 | 5.83333 |
| Mobile charged particles / relative units | 13.3333 | 6.66667 |
| Mobile charged particles / relative units | 15 | 7.5 |
| Mobile charged particles / relative units | 16.6667 | 8.33333 |
| Mobile charged particles / relative units | 18.3333 | 9.16667 |
| Mobile charged particles / relative units | 20 | 10 |
| Mobile charged particles / relative units | 21.6667 | 10.8333 |
| Mobile charged particles / relative units | 23.3333 | 11.6667 |
| Mobile charged particles / relative units | 25 | 12.5 |
| Mobile charged particles / relative units | 26.6667 | 13.3333 |
| Mobile charged particles / relative units | 28.3333 | 14.1667 |
| Mobile charged particles / relative units | 30 | 15 |
| Mobile charged particles / relative units | 31.6667 | 15.8333 |
| Mobile charged particles / relative units | 33.3333 | 16.6667 |
| Mobile charged particles / relative units | 35 | 17.5 |
| Mobile charged particles / relative units | 36.6667 | 18.3333 |
| Mobile charged particles / relative units | 38.3333 | 19.1667 |
| Mobile charged particles / relative units | 40 | 20 |
| Mobile charged particles / relative units | 41.6667 | 20.8333 |
| Mobile charged particles / relative units | 43.3333 | 21.6667 |
| Mobile charged particles / relative units | 45 | 22.5 |
| Mobile charged particles / relative units | 46.6667 | 23.3333 |
| Mobile charged particles / relative units | 48.3333 | 24.1667 |
| Mobile charged particles / relative units | 50 | 25 |
| Mobile charged particles / relative units | 51.6667 | 25.8333 |
| Mobile charged particles / relative units | 53.3333 | 26.6667 |
| Mobile charged particles / relative units | 55 | 27.5 |
| Mobile charged particles / relative units | 56.6667 | 28.3333 |
| Mobile charged particles / relative units | 58.3333 | 29.1667 |
| Mobile charged particles / relative units | 60 | 30 |
| Mobile charged particles / relative units | 61.6667 | 30.8333 |
| Mobile charged particles / relative units | 63.3333 | 31.6667 |
| Mobile charged particles / relative units | 65 | 32.5 |
| Mobile charged particles / relative units | 66.6667 | 33.3333 |
| Mobile charged particles / relative units | 68.3333 | 34.1667 |
| Mobile charged particles / relative units | 70 | 35 |
| Mobile charged particles / relative units | 71.6667 | 35.8333 |
| Mobile charged particles / relative units | 73.3333 | 36.6667 |
| Mobile charged particles / relative units | 75 | 37.5 |
| Mobile charged particles / relative units | 76.6667 | 38.3333 |
| Mobile charged particles / relative units | 78.3333 | 39.1667 |
| Mobile charged particles / relative units | 80 | 40 |
| Mobile charged particles / relative units | 81.6667 | 40.8333 |
| Mobile charged particles / relative units | 83.3333 | 41.6667 |
| Mobile charged particles / relative units | 85 | 42.5 |
| Mobile charged particles / relative units | 86.6667 | 43.3333 |
| Mobile charged particles / relative units | 88.3333 | 44.1667 |
| Mobile charged particles / relative units | 90 | 45 |
| Mobile charged particles / relative units | 91.6667 | 45.8333 |
| Mobile charged particles / relative units | 93.3333 | 46.6667 |
| Mobile charged particles / relative units | 95 | 47.5 |
| Mobile charged particles / relative units | 96.6667 | 48.3333 |
| Mobile charged particles / relative units | 98.3333 | 49.1667 |
| Mobile charged particles / relative units | 100 | 50 |
Explore: Change the fraction of mobile charge carriers. Relate the limits to a solid ionic lattice and a molten ionic sample.
Explain why solid sodium chloride does not conduct but molten sodium chloride does.
- Both contain ions, but the solid lattice fixes their positions.
- Melting allows charged ions to move and carry current.
Assumed knowledge
Ions, electrons and covalent bonds.
Learning checkpoints & source
YOUR LEARNING CHECKPOINT- Compare ionic, metallic, molecular and network structures.
- Distinguish pure substances, mixtures and carbon allotropes.