Unit 1: Quantum Theory

Question 1

Dalton

Answer 1

Matter is made up of small indivisible particles
- Billiard ball model

Question 2

J.J Thompson

Answer 2

e are embedded in a sphere of positive charge
- Chocolate chip cookie model

Question 3

Rutherford

Answer 3

Atoms are equally made up of e and p. There is a nucleus of positive charge in the middle.
- Nuclear model

Question 4

Maxwell

Answer 4

Light is an electromagnetic wave. c=lamdaf

Question 5

Planck

Answer 5

Energy emiited is not continuous but quantized. e exist only with energy which is multiple of a small quantity.
change in E=hf

Question 6

Problem with Rutherfords model

Answer 6

1) e would continuously emit radiation as they spiral towards the nucleus
2) Does not explain the empirical data of line spectra being shown. According to his model e would emit continous spectra.

Question 7

Einstein

Answer 7

Applied Plancks theory to light. Light emitted by a hot object is composed of photons of different E.

Question 8

Photoelectric Effect - Hertz

Answer 8

Enough E must be provided to ionize an e from its atom. Higher F = higher E = lower wavelength

Question 9

Bohr Postulates

Answer 9

1) Stationary State Postulate - e do not continuously radiate energy as they move around the nucleus. Each E-level corresponds to a constant state of E.
2)Transition Postulate - e can only change energy by transitioning from one E-level to another. To transition energy must be emitted or absorbed which is equal to the difference of energy between energy levels.

Question 10

Problem with Bohrs Model

Answer 10

1) only explains h line spectra
2) e are not completely descirbed as small particles

Question 11

Line Series

Answer 11

Lyman n=1, UV
Balmer n=2, visible
Paschen n=3, infared
Bracket n=4, infared

Question 12

Ionization Energy

Answer 12

The amount of energy required to “remove” an e from a neutral gaseous atom to produce a positive ion (cation)

X(g) + E(J) – X+(g) + e-

Question 13

De Broglie

Answer 13

Particles may have wave nature.
lamda = h/mv

Question 14

Aufbau Principle

Answer 14

“build it up principle”
States that shells and subshells are filled successively from lower E to higher E in a specififc order according to stability.

Question 15

Heisenberg Uncertainty Principle

Answer 15

States that one can never know both the exact position and momentum of an e at the same time.

Question 16

Schrodinger’s Wave Function

Answer 16

Represents the volume of space an e- is likely to be in (orbital)

Question 17

Hund’s Rule

Answer 17

States that In the ground state e- configuration, all orbitals of equal e are occupied first by a single e- with parallel spins before any orbital is occupied by a second e- pf opposite spin.

Question 18

Pauli Exclusion Principle

Answer 18

States that no two e- in the same atom can have the same four quantum numbers.