Atom: A Closer Look

Question 1

Empedocles

Answer 1

Proposed that matter was made of four elements: fire, water, air, and earth.

Question 2

They proposed that matter was made of particles so tiny that they could not be divided further.

Answer 2

Leucippus and his pupil Democritus

Question 3

Comes from the greek word for “not to cut”

Answer 3

Atom

Question 4

Declared that Leucippus and Democritus were wrong about matter so small that it is undivisible. (Atom)

Answer 4

Aristotle and Plato

Question 5

Conducted experiments that concluded that the atomic theory was true.

Answer 5

John Dalton

Question 6

He proposed the atomic theory in 1804.

Answer 6

John Dalton

Question 7

The Atomic Theory states that:

Answer 7

1. Matter is made of extremely small indestructible particles called “atoms”.
2. All atoms of a given element are alike.
3. Atoms can combine with other atoms to form compounds but remain unchanged during ordinary chemical reactions.
4. Atoms can combine in simple numerical ratios.

Question 8

Also known as electrons

Answer 8

Cathode rays

Question 9

Also known as protons

Answer 9

Canal rays

Question 10

The negative end of a gas tube

Answer 10

Negative electrode

Question 11

Discovered the electron after studying cathode rays.

Answer 11

Sir Joseph John Thompson

Question 12

Discovered the existence of positive particles which he called canal rays (now known as protons)

Answer 12

Eugen Goldstein

Question 13

Proposed the raisin bread model of the atom.

Answer 13

Sir Joseph John Thompson