Dalton’s atomic theory to the mass of atom free pdf 2022

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Dalton’s atomic theory to the mass of atom

Que 1-State the contribution of Dalton’s atomic theory to the mass of atom.What steps were taken to resolve this issue ?
Ans- Dalton’s atomic theory states that each atom has a characteristic mass and all atoms of an element are identical. Since, the mass of an atom is very very small, it was a difficult task to determine the mass of an individual atom. Therefore, it was decided to measure the atomic mass of an atom. Atomic mass is the relative atomic mass of an atom as compoared to some particular atom.

For example, carbon and oxygen combine to form carbon monoxide. It is observed that 3 g of carbon combines with 4g of oxygen. In other words carbon is 4/3 times its mass of oxygen. Since, oxygen combines with a large number of elements, oxygen atom was taken as standard and 1/16 of mass of oxygen was taken as one atomic mass unit (u). Now a days (1/12)th of the mass of C-12 isotope of carbon is taken as the standard reference for measuring atomic masses

Que 2 -The chemical symbol of sodium is Na. What is its significance ?
Ans- We know that the symbol of an element represents one atom of that element. Now
a days the first letter or first two letters of the name in English, Latin or German is used
as a symbol. It means that latin name of sodium starts with ‘N’.

Que 3- With the help of an example, state the significance of a symbol of an element.
Ans- The symbol of oxygen is ‘O’. As an example, let us give the significance of the symbol O’
(i) ‘O’ represents oxygen element.
(ii) ‘O’ represents one atom of oxygen element.

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Dalton's atomic theory to the mass of atom
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