Keeping in the view of chemical combination and the work of British chemist john Dalton Provided the basic theory about nature of matter known as Dalton’ s atomic theory.
The basic postulate of Dalton’s atomic theory are following.
Postulate:
- All matter is made up of tiny particles called atom which participated in chemical reactions.
For example,
- Atom are individual particles which can not be created or destroy in a chemical reactions
In a chemical reaction atom combine to form new unit. . Existing one can not be destroyed and new one can not be formed.
For example;
Only arrangement of atom occur. No new atom formation.
- Atom of given elements are identical in mass and chemical properties.
Both the atom have the same mass that is 16u and 16u chemical properties.
- Atom of different elements have different masses and different chemical properties.
Both have different masses and chemical properties.
- Atom combine in the ratio of small whole number to form compound.
Ratio combination of atom is always whole number.
H2O : 2:1
CO2: 1:2
HCl : 1:1
- The relative number and kind of atom are constant in a given compound.
H2O : 2 atom hydrogen
1 atom oxygen
CO2: 1 atom carbon
2 atom oxygen
HCl : 1 atom hydrogen
1 atom chlorine.
Merits of Dalton’s atomic theory:
- Dalton’s atomic theory provide us a conceptual picture of matter.
- Atom are the basic building blocks of the matter.
- They are smallest unit of an elements that can combine with other elements in a chemical reactions .
- In compound atom of two or more elements combine in a definite arrangements .
- The postulate of Dalton’s atomic theory “ atom can neither be created nor destroyed “. Was the result of law of conservation of mass.
- The postulate of Dalton’s atomic theory that the elements consist of atom having fixed mass. And that number and kind of atom in a given compound in a fixed ratio was the results of law of constant proportion.
Limitations/ Drawbacks of Dalton’s atomic theory:
- Atom is no longer considered as the smallest individual masses because it consists of sub atomic particles protons, neutron, and electrons.
- Atom of the same elements may have different masses.
- Atom of the same elements may have same masses.
- Substance made up of same kind of atom may have different properties.
Question answer:
1) Write the postulate of Dalton’s atomic theory?
Answer: Postulate of Dalton’s atomic theory are following.
- All matter is made up of tiny particles called atom which participated in chemical reactions.
- Atom are individual particles which can not be created or destroy in a chemical reactions.In a chemical reaction atom combine to form new unit. . Existing one can not be destroyed and new one can not be formed.
- Atom of given elements are identical in mass and chemical properties.
- Atom of different elements have different masses and different chemical properties.
- Atom combine in the ratio of small whole number to form compound.
- The relative number and kind of atom are constant in a given compound.
2) Write down the merits of Dalton’s atomic theory?
Answer:• Dalton’s atomic theory provide us a conceptual picture of matter.
- Atom are the basic building blocks of the matter.
- They are smallest unit of an elements that can combine with other elements in a chemical reactions .
- In compound atom of two or more elements combine in a definite arrangements .
- The postulate of Dalton’s atomic theory “ atom can neither be created nor destroyed “. Was the result of law of conservation of mass.
- The postulate of Dalton’s atomic theory that the elements consist of atom having fixed mass. And that number and kind of atom in a given compound in a fixed ratio was the results of law of constant proportion.
3) Write limitations of Dalton’s atomic theory?
Answer: • Atom is no longer considered as the smallest individual masses because it consists of sub atomic particles protons, neutron, and electrons.
- Atom of the same elements may have different masses.
- Atom of the same elements may have same masses.
- Substance made up of same kind of atom may have different properties.