Question

how many of the following statements regarding daltons atomic theory is/are still believed to be true?
i. elements are made of tiny particles called atoms.
ii. all atoms of a given element are identical.
iii. a given compound always has the same relative numbers and types of atoms.
iv. atoms are indestructible.

Explanation:

• Statement I: Dalton's atomic theory states that elements are made of tiny particles called atoms. This is still considered true as atoms are the basic building blocks of elements.
• Statement II: Dalton thought all atoms of a given element are identical. However, we now know about isotopes (atoms of the same element with different numbers of neutrons), so this is false.
• Statement III: Dalton proposed that a given compound always has the same relative numbers and types of atoms. This is in line with the law of definite proportions and is still true.
• Statement IV: Dalton believed atoms are indestructible. But with the discovery of nuclear reactions (like fission and fusion), atoms can be broken down or transformed, so this is false.

Answer:

C. 2 (Statements I and III are still believed to be true)