9/1 Concept Test Questions

1. Which one of the four postulates of Dalton’s Atomic Theory (1808) remains ture today?
A) All matter consists of atoms, tiny indivisible particles of an element that cannot be created or destroyed.
B) Atoms of one element cannot be converted to atoms of another element.
C) Atoms of the same element are identical in mass and other properties.
D) Compounds result from the chemical combination of a specific ratio of atoms of different elements.
E) None of the above remains true today.

2. Carefully consider the four postulates of Dalton’s Atomic Theory :
I) All matter consists of atoms, tiny indivisible particles of an element that cannot be created or destroyed.
II) Atoms of one element cannot be converted to atoms of another element.
III) Atoms of the same element are identical in mass and other properties.
IV) Compounds result from the chemical combination of a specific ratio of atoms of different elements.

Which of these postulates is no longer valid after the discovery of nuclear reactions (eg. 226Ra -> 222Rn + a-particle)?
A) I
B) II
C) III
D) IV