4.1

Question 1

the smallest unit of an element that maintains the properties of that element

Answer 1

atom

Question 2

a subatomic particle that has negative charge

Answer 2

electron

Question 3

in physical science an atoms central region which is made up of protons and neutrons

Answer 3

nucleus

Question 4

a region around the nucleus of an atom where electrons are likely to be found

Answer 4

electron cloud

Question 5

thought that matter is composed of atoms

Answer 5

Democritus

Question 6

Greek PHILOSOPHER, disagreed with Democritus. He believed that you would never end up with such particle that could not be cut. He had such a strong influence on peoples ideas that for a long time people thought he was right. He was right: matter is made of particles which we call atoms. An atom is the smallest particle into which an element can be divided and still be the same substance.

Answer 6

Artisole

Question 7

based his theory on observation of how elements combine

Answer 7

Dalton

Question 8

discovered electrons in atoms

Answer 8

Thomson

Question 9

discovered that atoms are mostly empty space with a dense, positive nucleus

Answer 9

Rutherford

Question 10

proposed that electrons are located in levels at certain distances from the nucleus.

Answer 10

Bohr