You are given a hammer, a battery, a bulb, wires and a switch. (a) How could you use them to distinguish between samples of metals and non-metals? (b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
Using a hammer: Strike the sample with a hammer. Metals are malleable and can be beaten into thin sheets, while non-metals break into pieces.
Using electrical circuit: Connect the sample in a circuit with battery, bulb, wires and switch. If the bulb glows, it is a metal (good conductor). If not, it is a non-metal (poor conductor).
These tests are useful for most metals and non-metals, but have exceptions. Graphite (non-metal) conducts electricity, and alkali metals (sodium, potassium) are soft. Using multiple tests together provides more reliable identification.
Explanation
(a) The chapter explains that metals are malleable (Activity 3.3) and good conductors of electricity (Activity 3.6). (b) The chapter mentions that elements cannot be grouped by physical properties alone due to many exceptions.