Quantum

Question 1

Waves

Answer 1

A vibrating disturbance by which energy is transmitted.

Question 2

Wavelength

Answer 2

The distance between successive crests of a wave, especially points in a sound wave or electromagnetic wave.

Question 3

Amplitude

Answer 3

The heights of the peaks or low troughs

Question 4

Frequency

Answer 4

The number of peaks or troughs that pass by a certain point in a certain amount of time

Question 5

True or False: High amplitude = higher brightness?

Answer 5

True

Question 6

Wavelength units of distance

Answer 6

(m/wave)

Question 7

Frequency units of time

Answer 7

(waves/s)

Question 8

Speed formula

Answer 8

distance/time or frequency x wavelength

Question 9

Frequency formula

Answer 9

speed/wavelength

Question 10

Wavelength formula

Answer 10

speed/frequency

Question 11

Maxwell hypothesis

Answer 11

Hypothesized that visible light
consisted of electromagnetic waves

Question 12

Electromagnetic radiation

Answer 12

The transmission of energy in the form of electromagnetic waves

Question 13

Electromagnetic waves

Answer 13

A form of radiation that travel though the universe, they do not need a medium (they travel through a vacuum)

Question 14

Electromagnetic waves travel at the same speed of

Answer 14

c = 2.998 x 10^8 m / s (in vacuum)

Question 15

Index of refraction

Answer 15

Ratio by which velocity of light slows down

Question 16

Albert Einstein did what

Answer 16

Used Mark Planck’s work on the photoelectric effect to show that under certain circumstances, light behaved more like particles NOT waves

Question 17

Photon

Answer 17

Is the smallest piece (quantum) of light

Question 18

Energy of photons formula

Answer 18

E = h x v

Question 19

Planks constant

Answer 19

h = 6.626 x 10^-34 J s

Question 20

Emission spectra

Answer 20

Specific frequencies given off are characteristics of the substance

Question 21

Emission spectra of atoms

Answer 21

Atoms (in gaseous state) do not emit all frequencies
Lines emitted by each element are specific to that element, they are like its fingerprint

Question 22

Johann Balmer

Answer 22

Derived a formula to explain the position of the lines in the visible region of the hydrogen spectrum

Question 23

Johannes Rydberg

Answer 23

Generalized to all regions (infrared and ultraviolet)

Question 24

Electron energy levels

Answer 24

These lines are the result of an electron going from one energy level to another

Question 25

If an electron goes up in energy it _____ If an electron goes down in energy it _____

Answer 25

1. Asorbs a photon 2. Releases a photon

Question 26

Ground state

Answer 26

Lowest energy state/level

Question 27

Excited states

Answer 27

All the other energy states/levels

Question 28

Rydberg formula

Answer 28

1/λ = R (1/n1^2 - 1/n2^2)

Question 29

Rydberg formula is expressed as

Answer 29

The energy difference between two levels This energy is equal to the energy of the photon that is absorbed or released during the transition

Question 30

Quantum number

Answer 30

Is the number (n)

Question 31

Hydrogen energy level

Answer 31

They are all negative, and the ground state is the lowest (most negative)

Question 32

The electrical pickle

Answer 32

When electrical current flows through a pickle, the sodium ions are excited to a higher energy level They emit yellow light as they relax down to ground state

Question 33

De Broglie’s Hypothesis

Answer 33

He linked Einstein’s idea about light having particle-like properties with electrons

Question 34

De Broglie’s formula

Answer 34

λ = h / p (p = m * v) Equation implies that a moving particle (mass m & speed v) has an associated wavelength given by λ If you have a wave (with a wavelength λ), it can exhibit particle-like properties (like having a mass) – wave-particle duality

Question 35

C. Davisson & G.P. Thomson

Answer 35

Showed that a beam of electrons could be diffracted by a sample in the same way as X-rays (which are waves)

Question 36

Advanced Atomic Theory

Answer 36

- Rydberg’s equation was a success for the hydrogen atom, but there were unanswered questions - Ex: Theory only worked for hydrogen and other one-electron systems like He+ and Li2+ (with a diff value for R) - Model was incomplete - If electrons are “wavelike”, then how do we define the position of the electron?

Question 37

Heisenberg’s Uncertainty Principle

Answer 37

States that it is impossible to know both the momentum and the position of a particle with certainty

Question 38

Heisenberg’s Uncertainty Principle formula

Answer 38

ΔxΔp≥ h/4π h = Planks constant ΔxΔp = Uncertainties

Question 39

Erwin Schrödinger

Answer 39

- Derived an equation that describes the energies and movement of subatomic particles - Equation combines both particle-like quantities (such as mass) and wave-like quantities such as Ψ, the wavefunction

Question 40

Wavefunction Ψ

Answer 40

Ψ has no physical meaning, but (Ψ2) is related to the probability of finding an electron in a certain region of space

Question 41

Electron density

Answer 41

Describes the probability of finding the electron at any given point at a given time; electron is most likely to be found where the value of Ψ2 is the greatest (highest electron density)

Question 42

Atomic orbital

Answer 42

Related to wavefunction of an electron in an atom – each orbital has a specific energy and distribution of electron density associated with it

Question 43

Quantum numbers

Answer 43

In quantum mechanics, each electron is classified by four quantum numbers

Question 44

1. Principle Quantum Number (n)

Answer 44

- (n) corresponds to the one for the Bohr atom - Can take positive integer values (1, 2, 3, etc.) - In hydrogen atoms (not other atoms), and completely defines the energy of the orbital - Determines the orbital's energy level and size. Higher values of n correspond to higher energy levels and larger orbitals.

Question 45

2. Angular Momentum Quantum Number (ℓ)

Answer 45

- (ℓ) gives the 3-D shape of the orbital and can range from 0 to n-1. - If n = 1, then ℓ can only be 0 - If n = 2, then ℓ can be 0 or 1 - ℓ is generally designated by a letter: s(1), p(2), d(3), f(4)

Question 46

Magnetic Quantum Number (mℓ)

Answer 46

- (mℓ) describes the orientation of orbital (e.g. along the x direction) - ml are integer values from -ℓ to +ℓ (-ℓ, -ℓ + 1, ... 0, ... ℓ - 1, ℓ) – If ℓ= 0, then mℓ must be 0 – If ℓ= 1, then mℓ can be -1, 0, or +1

Question 47

Level

Answer 47

A collection of orbitals with the same value of n (ex. 2s & 2p)

Question 48

Sublevel

Answer 48

One or more orbitals with the same value of n and ℓ (ex. 2p)

Question 49

s orbitals

Answer 49

- (ℓ = 0) are spherical in shape - Size of orbital increases as n increases - Value (phase) of wavefunction in all s orbitals is always positive - Larger values of n correspond to orbitals that have larger numbers of nodes

Question 50

p oribitals

Answer 50

- “dumb-bell” shape, with one lobe on either side of nucleus - Value (phase) of wavefunction (+ or -) is opposite on two sides of nodal plane - ℓ= 1, therefore there cannot be any p orbitals with n = 1 (n must be larger than ℓ), start at the n = 2 level - Each p sublevel consists of three orbitals (mℓ = -1, 0, +1), generally called px, py, and pz – no simple relation between the subscript and value of mℓ - All three orbitals are identical in size, shape, and energy

Question 51

d orbitals

Answer 51

- ℓ= 2, therefore there cannot be any d orbitals with n = 1 or n = 2, they start at the n = 3 level - Each d sublevel consists of five orbitals (mℓ = -2, -1, 0, +1, +2) - All five can be expressed in a form so they are identical in size, shape, and energy

Question 52

Nodes

Answer 52

Are areas of zero electron density