Chapter 6

Question 1

Wavelength (lambda)

Answer 1

Distance between two peaks (or two troughs)

Question 2

Frequency (nu)

Answer 2

Number of peaks to pass a given point per second

Question 3

Speed of light (c)

Answer 3

c = 3.00 • 10^8 m/s

Question 4

Speed of light equation

Answer 4

c = (nu)(lambda)

Question 5

As energy increases, wavelength __________ and frequency ____________

Answer 5

Wavelength decrease and frequency increases

Question 6

General order of the different types of radiation going from highest to lowest energy

Answer 6

Gamma, x-ray, ultraviolet, infrared, microwave, broadcast and wireless radio

Question 7

Angstrom (A with °)

Answer 7

10^-10 m, x-ray

Question 8

Nanometer (nm)

Answer 8

10^-9, ultraviolet

Question 9

Micrometer (um)

Answer 9

10^-6, infrared

Question 10

Millimeter (mm)

Answer 10

10^-3, microwave

Question 11

Centimeter (cm)

Answer 11

10^-2, microwave

Question 12

Meter

Answer 12

1 m, television, radio

Question 13

Kilometer (km)

Answer 13

10^3 m, radio

Question 14

Blackbody radiation

Answer 14

When the temperature of an object increases, it emits electromagnetic radiation of shorter and shorter wavelength, so higher and higher frequency

Question 15

Energy of 1 photon of light equation

Answer 15

E = h(nu)
E = (h • c)/(lambda)

Question 16

Planck’s constant

Answer 16

h = 6.626 • 10^-34 J•s

Question 17

Photoelectric effect

Answer 17

Light shining on a clean metal surface causes electrons to be emitted but only if the energy of the incoming light is above the work function of the metal

Question 18

What happens if a lot of photons strike the metal (increase the intensity)?

Answer 18

A lot of electrons are also ejected, but only if the photons possess enough energy to overcome work function

Question 19

What happens if higher energy photons (above the work function of metal) strike the metal?

Answer 19

The ejected electrons have greater kinetic energy due to conservation of energy

Question 20

Work function equation

Answer 20

E photon = (phi) metal + E k,electron

Question 21

We see different line spectra for different…

Answer 21

Elements

Question 22

Rydberg equation (line spectrum for hydrogen only)

Answer 22

1/(lambda) = (Rh)(1/((n1)^2 - (n2)^2))
Rh = 1.096776 • 10^7 m^-1
n1 and n2 are positive integers

Question 23

Bohr’s 1st postulate

Answer 23

Only orbits of certain radii, corresponding to certain specific energies, are permitted for the electron in a hydrogen atom

Question 24

Electronic energy levels in the hydrogen atom equation

Answer 24

E = (-hc(Rh))(1/n^2) = (-2.18 • 10^-18 J)(1/n^2)
n = principal quantum number (1, 2, 3, etc.)

Question 25

Why does energy of level increase (become more positive) as n increases?

Answer 25

Distance of electrons (-) from nucleus (+) increase, creating a greater potential energy

Question 26

Why are all of the energies negative values?

Answer 26

Attraction + and - charges

Question 27

What do you think the energy of electron is at an n=infinity?

Answer 27

Distance would go to infinity, so potential energy would get less and less negative, making it equal zero

Question 28

As the principal quantum number, n, increases for the hydrogen atom…

Answer 28

The energy levels converge (get closer and closer together)

Question 29

Bohr’s 2nd postulate

Answer 29

An electron in a permitted orbit is in an “allowed” energy stare. An electron in an allowed energy state does not radiate energy, and therefore does not spiral into the nucleus.

Question 30

Bohr’s 3rd postulate

Answer 30

Energy is emitted (n decreases) or absorbed (n increases) by the atom only when the electron changes from one allowed energy state to another. This energy us emitted of absorbed as a photon.

Question 31

If we let white light (photons with different energies) interact with the hydrogen atom…

Answer 31

When a photon strikes the electron with the right energy that matches the difference between energy levels, then that photon is absorbed and the electron is promoted to a higher energy level

Question 32

Equation to calculate light involved in a transition

Answer 32

Delta E = Ef - Ei = (-2.18 • 10^-18 J)(1/((nf)^2 - 1/(ni)^2))

Question 33

Light is involved ONLY…

Answer 33

When an electron undergoes a transition between energy levels

Question 34

If a hydrogen atom absorbs a photon

Answer 34

n increases, change in energy of the atom is positive

Question 35

If a hydrogen atom emits a photon

Answer 35

n decrease, change in energy of the atom is negative

Question 36

de Broglie wavelength equation

Answer 36

Lambda = h/(m • nu)

Question 37

Constructive interference

Answer 37

The amplitude of two waves is added

Question 38

Destructive interference

Answer 38

The amplitude of two waves is subtracted

Question 39

Heisenberg’s uncertainty principle equation

Answer 39

(Delta x)(delta m•nu) >= h/(4pi)

Question 40

de Broglie and matter waves

Answer 40

An electron can behave like a wave and a particle

Question 41

Heisenberg and the uncertainty principle

Answer 41

It is impossible to precisely know two measured values at the same time. The energy will be quantized and precisely known, so the position is described in terms of probability