Two kinds of element
Tap a metal strip and it rings. Tap a lump of coal and it stays silent.
Step 1 of 2
- Graphite shines and conducts, so it looks like a metal. Mercury is a liquid, so it looks like a non-metal.
- Graphite is a non-metal and mercury is a metal. Looks alone can mislead.
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The rule
Metals are usually shiny, bendable, ringing and good conductors. Non-metals are usually dull, brittle and poor conductors. Brittle means breaking when hit. A conductor lets heat or current pass.
| Property | Metals | Non-metals |
|---|---|---|
| Shine | Usually yes | Usually no |
| Hammered flat or drawn into wire | Usually yes | Usually no, they break |
| Rings when struck | Usually yes | Usually no |
| Conduct heat and electricity | Usually yes | Usually no |
Some elements break these rules.
| Element | The surprise | Kind |
|---|---|---|
| Graphite | Conducts current | Non-metal |
| Diamond | Very hard | Non-metal |
| Iodine | Shiny | Non-metal |
| Mercury | Liquid at room temperature | Metal |
| Sodium | Soft enough to cut | Metal |
Worked example
Mercury is a liquid, which is rare for a metal. It still shines and conducts, so it is a metal. Graphite shines and conducts too. Yet graphite is a non-metal, a form of carbon. So looks and conduction alone cannot settle the kind.