History

Question 1

Where and when did the idea of the atom originate? By who?

Answer 1

Ancient Greece (400 B.C.)
Democritus and Leucippus (Greek philosophers)

Question 2

What is the modern model of the atom called?

Answer 2

The BOHR model

Question 3

What was the (incorrect) theory that Aristotle and Plato favored?

Answer 3

Earth, air, fire, and water approach to the nature of matter

Question 4

What was Dalton’s atomic theory? (3 sentences)

Answer 4

• All matter is made of invisible particles called atoms.
• Atoms of the same element are identical, those of different elements are different.
• Atoms of different elements combine in whole number ratios to form compounds.

Question 5

What was Dalton’s model (#1) of the atom?

Answer 5

Billard Ball Model

Question 6

What did Crookes discover/invent?

Answer 6

Cathode Ray Tube

Question 7

What did Sir JJ Thomson discover? Using what? And what model did he use?

Answer 7

Electrons, Cathode Ray Tube, Plum Pudding Model

Question 8

What are the characteristics of Thomson (#2) model of the atom?

Answer 8

The atom is a solid, positively charged sphere with negative electrons scattered throughout.

Question 9

What are the pros of Thomson’s model of the atom?

Answer 9

• Introduces the idea of charged particles within the atom
• Discovers the electron (1st subatomic particle)

Question 10

What are the cons of Thomson’s model of the atom?

Answer 10

• Atom solid sphere
• Doesn’t explain future experiments

Question 11

What did Millikan and Rutherford determine?

Answer 11

Mass and charge of an electron (9.1 x 10^-28)

Question 12

What was Rutherford’s experiment? What are the characteristics?

Answer 12

The Gold Foil Experiment
Used a zinc sulfide coated screen to detect radioactive alpha particles

Question 13

What was the outcome of Rutherford’s experiment?

Answer 13

Alpha particles bounced back at him

Question 14

What does Rutherford Model (#3) of the atom look like?

Answer 14

Atom is mostly empty, small dense positive nucleus in the center, electrons scattered around the nucleus

Question 15

What did Niels Bohr propose?

Answer 15

He proposed a new improvement to the atomic model where electrons have definite energy levels around the nucleus. (#4 Planetary Model)

Question 16

What is a quanta of energy?

Answer 16

The amount of energy needed to move an electron from one energy level to another.

Question 17

What is a photon?

Answer 17

The minimum energy to release an electron out of an atom.
(Light particles)

Question 18

What did Moseley discover?

Answer 18

Protons

Question 19

What did Chadwick discover?

Answer 19

Neutrons

Question 20

What did Heisenberg discover? Describe it?

Answer 20

The Uncertainty Principle
- The more precisely the position of an electron is determined, the less precisely the momentum is known in that instant (and vice versa)

Question 21

What did Schrodinger create?

Answer 21

The current model of the atom
(#5) Charge-Cloud Model or Quantum Mechanical Model

Question 22

What is an orbital?

Answer 22

3D mathematical probability regions where an electron can live

Question 23

What are the Keeps?

Answer 23

The concept of energies being quantized in certain energy levels

Question 24

What are the Discards?

Answer 24

2D concept of orbits discarded in favor of orbitals

Question 25

What does a S-Orbital diagram look like?

Answer 25

Spherical

Question 26

What does a P-Orbital diagram look like?

Answer 26

Dumbell