SANCHO'S The Atom Lesson Notes For Advanced Level
INTRODUCTION:
An atom is the smallest particle of an element that has all the chemical properties of that
element.
Matter is anything that occupies space, possesses mass, offers resistance and can be felt by one
or more of our senses. In this unit we are going to cover basics like atomic structure and
bonding between atoms. Molecules are made up of atoms held together by Special
Forces = bonds.
DALTON’S ATOMIC THEORY:
In 1808, the British chemist John Dalton formulated his atomic theory matter.
The main
points of Dalton’s atomic theory are as follows:
1. Matter is made up (composed) of extremely small, indivisible particles, called atoms.
2. Atoms of same substance are identical in all respects, i.e., they possesses same size, shape,
mass, and chemical properties.
3. Atoms of different substances are different in all respects. This means that, the atoms of one
element differ from the atoms of other elements
4. Atoms of different element may combine with each in a fixed, simple, whole number ratio to
form compound atoms.
5. Atoms can neither be created nor destroyed, i.e., atoms are indestructible
