Lesson 12 of 14
The big picture
Show on a big screenTen ideas. And one grey pencil core that shows one test is not enough.
| Idea | Remember | Example |
|---|---|---|
| Shine and sound | Lustre and sonorous are tests, not looks. | A glass marble shines but is not a metal |
| Beaten and drawn | Malleable spreads. Ductile draws into wire. | Foil is beaten thin |
| Warmth and the loop | Metals carry both well. | Graphite carries the loop, but is not a metal |
| Non-metals around us | State and metal-or-not are separate questions. | Mercury is a liquid metal |
| Rusting | Air and water together, or nothing happens. | A dry nail stays bright |
| Choosing | The job decides which property matters. | Copper fits a lamp's flex. Aluminium fits food foil. The job decides. |
| Oxides | A metal's oxide is usually basic. A non-metal's oxide is usually acidic. Litmus in water can show which, if the oxide dissolves. | Magnesium oxide: basic. Sulfur dioxide: acidic |
| Kept away | Keep a substance away from what it reacts with. Sodium reacts with air and water, so it is kept in kerosene. White phosphorus can catch fire in air, so water covers it. | Sodium under kerosene |
| Jewellery | A jewellery metal shines and shapes easily. It keeps its shine in air and water. Of iron, copper, silver and gold, gold does this best. | A gold bangle stays bright |
| Non-metal jobs | Non-metals do vital jobs. Chlorine cleans water. Iodine is an antiseptic for wounds. Nitrogen is in fertilisers. Oxygen is for breathing. Carbon is in all living things. | Chlorine in drinking water |
Now open Chapter 4 in your NCERT book. Ask of each question: which property does the job need?