Elements are divided into metals, non-metals and metalloids based on their properties. This topic links chemistry with daily-life uses and is common in SSC and Railway exams.
Properties of Metals
- Shiny (lustrous), hard and strong.
- Good conductors of heat and electricity.
- Malleable (can be beaten into sheets) and ductile (drawn into wires).
- Mostly solid; exception is mercury, which is liquid.
Properties of Non-Metals
- Mostly dull, brittle and soft.
- Poor conductors; exception is graphite, which conducts.
- Can be solid, liquid or gas. Bromine is a liquid non-metal.
Reactivity Series
The reactivity series arranges metals by reactivity. Potassium is the most reactive and gold is among the least reactive. A more reactive metal displaces a less reactive one from its salt.
Advertisement
Alloys
- Brass = copper + zinc.
- Bronze = copper + tin.
- Steel = iron + carbon.
- Stainless steel = iron + chromium + nickel.
Important Facts
Silver is the best conductor of electricity. Gold and platinum are called noble metals because they do not corrode easily. Sodium and potassium are stored in kerosene because they react with air and water.
Quick Revision Points
- Mercury is the only liquid metal.
- Graphite is a non-metal that conducts electricity.
- Silver is the best electrical conductor.
- Brass = copper + zinc.
- Most reactive metal is potassium.
- Sodium is stored in kerosene.
- Metals are malleable and ductile.