On ramps chem unit 1 review

Rutherford's gold foil experiment demonstrated that

the positive charge in an atom must reside in a dense core much smaller than the atom (the nucleus)

Rutherford’s foil experiement proved the existance of the nucleus

Which scientist is associated with the discovery of the electron?

JJ Thompson discovered the electron in 1897 by demonstrating that cathode rays were negatively charged

One of hte most profound ideas proposed by Max Planck was

Electron energies are quantized— he showed that the structure of nature is discontinuous and was restriced to discreet values, forming the conclusion that electromagnetic energy could only be used in quantized form

when an atom absorbs a photon of light, electrons

move up an energy level

an electron moving from the 3rd energy level to the 1st energy level will

emit a photon, when an electron moves down energy levels, they release energy in the form of light

the electromagnetic spectrum

is divided into 7 named regions, each containing a range of wavelengths

wavelength and frequency are

inversely proportional

light propogates in

both electric and magnetic fields

radio waves

lowest energy level, cause nuclei to flip their spin

microwaves

low energy radiation, contains enough energy to cause entire molecules to rotate

Infrared radiation

higher energy, causes vibrations in molecules, can change mode of vibration

UV and visible light

energetic enough to excite the valence electrons, ionizing radiation

x-rays and gamma rays

highest energy, can penetrate the inner shell electrons

delta E is change in energy

v is the frequency (s^-1)

lamda is wavelength (m)

c is speed of light (3×10^8 m-s)

h is panks constant (6.6×10^-34)

destructive interference of two waves occur when

the two waves are exactly out of phase

the three failures of classical physics

1. emission spectra of hydrogen

2. blackbody radiation

   1. photoelectric effect

The photon…

teh model of light as a particle

E=hv

wave particle duality

the question of if light is a wave or a particle?

One of the pieces of evidence supporting energy quantization was the line spectra of elements. Why does this demonstrate energy quantization?

There are sharp emission lines demonstrating discrete energy levels.

the photoelectric effect

use of a photon to produce an electron

Increasing the brightness (i.e. more photons of the same energy) of the light shined on the metal _____ the number of ejected electrons.

increases

Increasing the _____ of light can increase the speed of the ejected electrons. 

frequency

In the 20th century, quantum mechanics addressed the failures of classical mechanics by introducing the concept of the wave-particle duality. Why was classical mechanics able to explain the world just fine up until then?

Macroscopic objects can be modeled purely as particles because their wavelength is so small compared to their scale that it can be neglected for most purposes and still gives a good description of their behavior.

You shoot a beam of 4.5 eV light at a metal surface and notice that electrons are being released from the metal. What will happen if you then increase the intensity of the 4.5 eV light?

more electrons would be released

light behaves like

both a particle and a wave

Einstein's explanation for the photoelectric effect led to what major breakthrough in science?

wave particle duality of light

Which of the following experiments most directly supports de Broglie's hypothesis of the wave nature of matter?

 

Electron diffraction by a crystal

Even though all matter exhibits a wave-like quality, we can really only observe the wave properties of

very small objects like subatomic particles.

n- principle quantum number

explains energy levels and sitance of electrons from the nucleus

l- angular momentum number

explains shape of atomic orbital

s-1

p-3

d-2

f-4

m_l- magnetic moment

explains orientation of atomic orbital

s-0

p- -1 0 1

d- -2 -1 0 1 2

f- -3 -2 -1 0 1 2 3

m_s- electron spin

explains orientation of electron spin

if the last electron is an up arrow it’s +1/2 or if it’s negative it’s -1/2

The Rydberg constant is 3.3 x 10¹⁵ Hz. This value is also

the ionization frequency of hydrogen

What is the frequency of light released when an electron moves from the 2nd energy level to the 1st energy level in hydrogen (don't reach for a calculator, you should be able to estimate 3/4s of a number like 3.3).

2.5 x 10¹⁵ Hz

Schrodinger's solution to the wave equation that agreed with the Rydberg constant proved what?

Electrons have a wave like character and can be solved with wave equations.

The complication to the Schrodinger equation in multi-electron systems arises because:

electrons repel each other

Aufbau principle

Always fill electron orbits starting with the orbits that are closest to the nucleus. This is the lowest energy or ground state configuration.

pauli exclusion principle

Never put more than 2 electrons in a single orbit. This is actually the consequence of a larger idea promoted  by Pauli  that no two electrons can have the same four quantum numbers.

huds rule

bus seats, fill up one by one before doubling up