DALTON’S ATOMIC THEORY
Most of the universe consist of matter and energy. Energy is the ability to do work. Matter has mass
and occupy space.
All matter is composed of basic elements that cannot be broken down to substances with different chemical and physical properties.
There are about 115 different elements which have been discovered; each is chemically unique. That means that they behave different in forming molecules and reacting with other element and molecules.
According to the concept of the ancient Greek philosophers, atoms are known as the smallest particle in which an element can divide. Dalton considered atom as a fundamental particle of an element that could not be broken down. However the discovery of Enrico Fermi and his colleagues proved that atom is divisible.
DALTON’S ATOMIC THEORY
1. All matter is composed of atom.
2. Atoms cannot be created, divided or destroy.
3. All atoms of one element are alike, and different from those of any other element.
4. Atoms combine together in ratio of small whole number to form compound.
MODIFICATION OF DALTON’S THEORY
1. Atoms can be subdivided into electrons, protons, and neutrons.
2. Atoms of an element maybe different (isotope)
3. Some atoms e.g. carbon, that forms ring and long chains from giant molecules containing thousands of atoms. This indicates that combination of atoms can form a compound that may not be in a ratio of small whole numbers
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Source:
http://skulscholars..com/2019/01/daltons-atomic-theory.html

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