Question

Which of the following is(are) not a postulate(s) of Dalton's atomic theory?

• A. Atoms are neither created nor destroyed in a chemical reaction.
• B. The relative number and kinds of atoms are constant in a given compound.
• C. Atoms of all elements are alike, including their masses.
• D. Each element is composed of extremely small particles called atoms.

Answer 1

Answer: (C)

Atoms of all elements are alike, including their masses.

The main assumptions or postulates of Dalton are :

• All matter consists of indivisible particles called atoms.
  
• Atoms of the same element are similar in shape and mass but differ from the atoms of other elements.
  
• Atoms cannot be created or destroyed.
  
• Atoms of different elements may combine in a fixed, simple, whole number ratio to form compound atoms.
  
• Atoms of the same element can combine in more than one ratio to form two or more compounds.
  
• Atoms are the smallest unit of matter that can take part in a chemical reaction.
  

Hence option (C) is the correct answer.