Chapter 7(Exam 2)

Question 1

Isaac Newton

Answer 1

Was able to explain how and why rainbows appear. When sunlight passes through a prism, it is separated into its components. Colors recombined into white sunlight with a second prism

Question 2

Fraunhofer lines

Answer 2

Dark lines that appear in the optical spectrum of the sun, shown to be absorption lines of atoms

Question 3

Atomic emission spectrum

Answer 3

a series of bright lines produced by high temperature atoms

Question 4

Atomic absorption spectrum

Answer 4

A series of dark lines produced when free, gaseous atoms are illuminated by a continuous source of radiation

Question 5

Electromagnetic spectrum from smallest to largest wavelengths

Answer 5

gamma rays
x rays
ultraviolet rays
visible waves
infrared waves
microwaves
radiowaves

Question 6

electromagnetic radiation

Answer 6

a form of energy that has wave characteristics and propogates through a vacuum at a characteristic speed(c)

Question 7

amplitude

Answer 7

the height of the crest or depth of the trough of a wave

Question 8

diffraction

Answer 8

bending of waves around obstacles

Question 9

interference

Answer 9

the superposition of waves when they combine to form a new wave

Question 10

refraction

Answer 10

the bending of waves as the change mediums

Question 11

Max planck

Answer 11

explained blackbody radiation by assuming the energy emitted by heated solids is quantized

Question 12

Photon

Answer 12

Quantum of electromagnetic radiation

Question 13

Quantized/unquantized states

Answer 13

Quantized: discrete energy levels(steps)

Unquantized: Smooth transition between levels

Question 14

Photoelectric effect

Answer 14

Phenomenon of light striking a metal surface and producing an electric current, explained by Albert Einstein using plancks equation

Question 15

blackbody radiation

Answer 15

the amount of electromagnetic radiation emitted as a function of frequency as a result of heating solids

Question 16

What happens if the radiation described in the photoelectric effect is below threshold energy?

Answer 16

no electrons are released

Question 17

Threshold frequency

Answer 17

(vo) the frequency needed to dislodge electrons from the metal surface, unique to each metal

Question 18

work function

Answer 18

the minimum energy required to produce the photoelectric effect

work function=h(vo)

Question 19

What if the frequency exceeds the threshold frequency?

Answer 19

v>vo, kinetic energy of ejected electrons can be found by using KE=hv-work function

Question 20

Wave-particle duality

Answer 20

Light/radiant energy has properties of both a wave and a particle

wave characteristics: has wavelength and frequencies

Particle characteristics: photoelectric effect, quantized packets of energy

Question 21

Johann Balmer

Answer 21

Determined wavelengths of four brightest lines in the H emission spectrum

wavelength=364.5•(m^2)/(m^2-n^2)

n=2, m>n

Question 22

Johannes Rydberg

Answer 22

Revised Balmer’s equation by changing wavelength to wavenumber

1/wavelength=(1.0097•10^-2 nm^-1)(1/n1^2 - 1/n2^2)

Question 23

Wavenumber

Answer 23

1/wavelength, the number of cycles of the wave in a given length

Question 24

Empirical formula for hydrogen atom spectrum and it’s alternate form

Answer 24

1/wavelength=R(1/na^2 - 1/nb^2)

R=Rydberg constant= 1.097373•10^7 nm^-1

nb>na, both are positive integers

v=C(1/na^2 - 1/nb^2)
C=Rc=3.29•10^15 s^-1
nb>na

Question 25

Bohr’s number

Answer 25

En=-hcR(1/n^2)

hcR=2.179•10^-18

for one electron ions, use Z^2 instead of 1 with Z denoting the atomic number

Question 26

Characteristics of electrons in H atoms

Answer 26

1. Occupy discrete levels and exist only in the available energy levels
2. Can move in between energy levels by absorbing or admitting energy
3. Have energy levels designated by a specific value for n

Question 27

Difference between energy levels formula

Answer 27

🔼E=-2.178•10^-18 J(1/nfinal^2 - 1/ninitial^2)

Question 28

Ground/excited states for hydrogen atoms

Answer 28

Ground state: E1, lowest energy level

First excited state: E2

Second excited state: E3

etc.

Question 29

Absorption/emission

Answer 29

Absorption: Transition from a lower to a higher energy state, +🔼E

Emission: Higher energy state to lower energy state, -🔼E

Question 30

Bohr model strengths and limitations

Answer 30

Strengths
1. Accurately predicts energy needed to remove an electron from an atom(ionization)

2. Allowed scientists to begin using quantum theory to explain matter at the atomic level

Limitations
1. Does not account for spectra of multielectron atoms

2. Movement of electrons in atoms is less clearly defined than Bohr allowed

Question 31

Wavelength/frequency formula

Answer 31

c=(wavelength)v

Question 32

Difference between energy levels

Answer 32

🔼E=-2.178•10^-18(1/nfinal^2 - 1/ninitial^2)