5.1 Atomic Theory

Question 1

Law of Definite Proportions

Answer 1

In a given type of chemical substance, the elements always combine in the same proportions by mass.

Question 2

Law of Multiple Proportions

Answer 2

When two elements react to form more than one substance, and the same amount of one element is used in each substance, then the ratio of the masses used of the other element will be in small whole numbers.

Question 3

Dalton Atomic Theory

Answer 3

1. Matter is composed of tiny particles called atoms (as well as molecules and ions).
2. Atoms are indivisible. During a chemical reaction, atoms are rearranged, but they do not break apart, nor are they created or destroyed.
3. All atoms of a given element are identical in mass and other properties.
4. The atoms of different elements differ in mass and other properties.
5. Atoms of one element can combine with atoms of another element to form compounds. In a given compound, however, the different types of atoms are always present in the same relative numbers.

Question 4

atomos

Answer 4

Democritus’ word for the tiny, indivisible, solid objects that he believed made up all matter in the universe.