science
Grade-9
Easy
Question
Which of the following failed the existence of Dalton’s theory?
- Compounds
- Molecules
- Allotropes
- Alloys
Hint:
Dalton proposed that all elements are made up of atoms that have similar properties.
The correct answer is: Allotropes
- Allotropes failed the existence of Dalton's theory.
- According to Dalton, all substances are made up of tiny, indivisible units known as atoms. He followed that all atoms of a specific element are of the same in size, mass, and properties.
- On the other hand, allotropes are the compounds of one or more forms of a chemical element that occur in the same form of physical state. For example, allotropes of carbon are graphite and diamond. Here, both belong to the same element but possess different properties which contradict Dalton's theory.
Dalton's theory is even disproved by the presence of isotopes.
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