Page 2 - 3. Lesson Notes- Ch-3 Physical properties of Metal & Non metals) - PDF)

oor
P
5. Electrical Good conductor of electricity ductor of electricity
n
co

conductivity Best conductor- Silver followed Exception- Graphite (In graphite
by copper very C-atom is bonded to three
e
Poor conductor- Iron & Mercury other C-atoms, such that each
carbon has one free electron
which helps in conducting
electricity.

6. Luster Usually Lustrous Usually Non Lustrous (Dull
surface)
Exception- Iodine

7. Sonorous Usually sonorous Usually non sonorous

8. Hardness Usually Hard Usually soft and brittle
Exception- Na, K can be cut Exception- Diamond is the
with a knife hardest naturally found material
on the Earth’s crust.

9. Melting Usually have high Melting Usually have low Melting point
point point
Exception- Carbon & Silicon
Exception- Gallium & Caesium
o
(have a very low M.P. of 29 C &
o
28 C respectively)
Li, Na & K also have low MP.

10. Density Usually have High Density Usually have Low Density
L
igh
t
Lightest metal – Lithium est nonmetal - Helium
Heaviest metal- Osmium viest nonmetallic - Astatine.
a
e
H
Li, Na & K also have low
density.

• Allotropes- The different forms of an element having different structures
and different physical properties but same chemical properties are known as
Allotropes.

Example- 1. Diamond & Graphite are allotropes of Carbon.

2. Red & White/Yellow are allotropes of Phosphorus.

3. Rhombic and Monoclinic sulphur are allotropes of Sulphur.

4. Oxygen gas (O2) & Ozone (O3)gas are allotropes of Oxygen.

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