Chapter 4 Atomic Structure

Question 1

What is an atom ?

Answer 1

An atom is the smallest particle of an element that retains its identity in a chemical reaction.

Question 2

Who was Democritus?

Answer 2

The Greek philosopher who was among the first to suggest the existence of atoms. “Atoms are indivisible and indestructible”

Question 3

Who was John Dalton?

Answer 3

An English chemist and schoolteacher. Used experimental methods to transform Democritus’ ideas on atoms into a scientific theory.

Question 4

Dalton’s Atomic Theory

Answer 4

1. All elements are composed of tiny individual particles called atoms.
2. Atoms of the same elements are identical. The atoms of any one element are different from those of any other element.
3. Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds.
4. Chemical reactions occur when atoms ate separated from each other, joined, or rearranged in a different combination. Atoms of one element, however, are never changed into atoms of another element as a result of a chemical reaction.