Elements
o Elements:
An element is a pure substance that consists of only one type of atom. It cannot
be broken down into a simpler substance by chemical means.
→ Note:
a) Each element is made up of atoms that have the same number of protons in
their nucleus.
b) There are 118 known elements.
Types of Elements:
Elements
Metal Non-metal Metalloid/Semi-
metal
1 Metal
A metal is an element that is shiny, hard, malleable, and a good
conductor of heat and electricity.
Location in Periodic Table: Left and center.
Example: Iron, Copper
🔩 Physical property of metal:
1. Lustrous (Shiny Appearance):
o Metals have a shiny surface.
o They reflect light when freshly cut or polished.
Example: Gold, silver, copper.
2. Hardness
, o Most metals are hard and strong.
o They cannot be easily broken or scratched.
Exception: Sodium and potassium are very soft and can be cut with a knife.
3. Malleability
o Metals can be hammered into thin sheets.
o Used in making foils and decorative items.
Example: Aluminium foil, gold foil.
4. Ductility
o Metals can be drawn into wires.
o Used to make electric wire.
Example: Copper and aluminium wires used in electricity.
5. Conductivity
o Metals are good conductors of heat and electricity.
Example: Copper is widely used in electrical wiring.
Aluminium is often used to make stencils because:
6. Sonorous (Metallic sound)
o Metals produce a ringing sound when struck.
Example: Bells are made of metal due to this property.
7. High Melting and Boiling Points
o Most metals melt and boil at high temperatures.
Exception: Mercury is a liquid metal at room temperature.
8. High Density
o Metals are generally heavy for their size.
o Elements:
An element is a pure substance that consists of only one type of atom. It cannot
be broken down into a simpler substance by chemical means.
→ Note:
a) Each element is made up of atoms that have the same number of protons in
their nucleus.
b) There are 118 known elements.
Types of Elements:
Elements
Metal Non-metal Metalloid/Semi-
metal
1 Metal
A metal is an element that is shiny, hard, malleable, and a good
conductor of heat and electricity.
Location in Periodic Table: Left and center.
Example: Iron, Copper
🔩 Physical property of metal:
1. Lustrous (Shiny Appearance):
o Metals have a shiny surface.
o They reflect light when freshly cut or polished.
Example: Gold, silver, copper.
2. Hardness
, o Most metals are hard and strong.
o They cannot be easily broken or scratched.
Exception: Sodium and potassium are very soft and can be cut with a knife.
3. Malleability
o Metals can be hammered into thin sheets.
o Used in making foils and decorative items.
Example: Aluminium foil, gold foil.
4. Ductility
o Metals can be drawn into wires.
o Used to make electric wire.
Example: Copper and aluminium wires used in electricity.
5. Conductivity
o Metals are good conductors of heat and electricity.
Example: Copper is widely used in electrical wiring.
Aluminium is often used to make stencils because:
6. Sonorous (Metallic sound)
o Metals produce a ringing sound when struck.
Example: Bells are made of metal due to this property.
7. High Melting and Boiling Points
o Most metals melt and boil at high temperatures.
Exception: Mercury is a liquid metal at room temperature.
8. High Density
o Metals are generally heavy for their size.
