Page 1 - 3.Lesson Note-Elements,compounds and mixtures

SAI International School
Subject-Chemistry
Ch-Is Matter around us pure?

Topic-Elements, compounds and Mixtures
LESSON NOTE

Elements are the basic and simplest form of matter that cannot be broken down
further to give other chemical substances by chemical reactions.

Characteristics of elements:

1. They are composed of same kind of atoms.
2. They can not be converted into anything simpler.
3. They are pure and homogeneous.
4. They have fixed melting and boiling points
5. There are nearly 118 elements (at present) of which nearly 94 occur naturally
on Earth.
6. On the basis of their characteristic properties, elements are divided into
metals, non-metals and metalloids.
7. Examples: Iron(Fe), Sodium (Na), Oxygen (O) etc.

Classification of elements :

Metals:

1. Metals have shiny surface called metallic lustre.
2. Metals are malleable.
3. Metals are ductile
4. Metals are sonorous
5. Metals are good conductors of heat and electricity.
6. Metals are usually solids at room temperature except mercury which is a
liquid at room temperature.
Non-metals:

1. Non-metals have dull surface.
2. Non-metals are nonmalleable.
3. Non-metals are nonductile
4. Non-metals are non sonorous
5. Non-metals are bad conductors of heat and electricity.
6. Non-metals are usually solids liquids or gases at room temperature.