Chem 2, Exam 1

When letters are in "" they are a quantum number

f

10^-15

p

10^-12

n

10^-9

mu

10^-6

m

10^-3

c

10^-2

P

10¹⁵

T

10¹²

G

10⁹

M

10⁶

K

10³

h

10²

Angstrom

10^-10

Relationship between wavelength, frequency, and amplitude with energy of light as a wave

As wavelength decreases, frequency increases. As frequency increases, energy increases. As amplitude increases, energy increases

Photoelectric Effect

Electrons sometimes get ejected off a metal when light is shown on it. Photons aren’t particles because they exhibit interference or diffraction the way waves do but do hold traits characteristic of particles such as being detectable as individuals.

Emission spectrum

What was being measured in the spectrometers, the wavelengths emitted when electrons relax

What are the problem experiments? What was the main issue?

Photoelectric Effect and emission spectrum, the more a photon is observed as a particle or wave, the less it looks like the other.

How does the wavelength and frequency of a wave effect electrons?

As frequency increase, the photon becomes larger, larger photons expels the electrons faster.

How does the amplitude of light effect electrons?

More amplitude means more photons, leading to more electrons being dispersed.

Binding energy

The minimum energy needed to repel an e. Minimum frequency, maximum wavelength.

Threshold frequency

The frequency found by E=hv, where “E” is the energy necessary aka the binding energy.

Calculate KE

Energy of photon minus energy of binding energy.

Pauli’s exclusion principle

No two identical electrons can occupy the same quantum state. There can’t be two (-1/2) for M_s

Aufbau principal

Electrons take up space that is most stable first. (where they have the lowest energy)

Hund’s rule

Maximize the same spin in degenerate orbitals. (spread out before sharing rooms)

Core/inner electrons

Electrons not on the outer shell

Outer electrons

The electrons on the outermost shell

Valence electrons

The electrons in the partially filled orbitals

Relationship between nodes and energy

more nodes, means more energy

“n”

The principle QN is the energy level, which has to be equal to or more than 1. Gives a general idea of the distance from the nucleus.

“L”

The Angular QN, describes the number of subshells, number of nodal planes and the shape.

“m_L”

 Magnetic QN, the amount of possible m_L’s describes the number of orbitals possible and the number it is describes the orientation within the subshell

“m_s”

Spin QN, -½ is a downward spin and +½ is an upward spin.

When might the de Broglie wavelength be irrelevant?

When the wavelength creates is very small compared to the object.

Penetration (in chem)

 The ability of an e- to get closer to the nucleus. The closer to the nucleus the more penetrating power.

Shielding

How electrons repel one another; the way that core electrons repel valence electrons, so those valence electrons don’t get as close to the nucleus.

Amount of nodes

Equal to n-1

Define ionization energy

The energy it takes to remove an electron. Always positive. Makes an element less stable because it breaks attraction, the protons within an element have fewer negative charges to hold onto. Endothermic.

Define Energy Affiliation

The energy it takes to give an element another electron. Usually negative since elements tend to easily take the electron but if the electron was forced on the electron, it is positive. Makes an element more stable because it allows attraction. Exothermic.

Explain the break in trend between 5A and 6A

5A gets less stable when an electron is removed because it would go from 1s^2 2p^3 to 1s^2 2p^2, while 2p^3 is filled to a stable level while 2p^2 isn’t filled and therefore less stable. 6A gets more stable when an electron is removed because it would go from 1s^2 2p^4 to 1s^2 2p^3, while 2p^4 isn’t filled to a stable level while 2p^3 is and therefore more stable.

What is the Heisenberg Uncertainty Principle?

The Heisenberg Uncertainty equation shows that uncertainty of position and uncertainty of momentum are inversely proportional, leading to the Heisenberg Uncertainty Principle which means the more certain the position is the more uncertain the momentum. While position may be more certain if viewing an electron as a particle doing such give a very uncertain momentum, and vice versa. This makes it impossible to think of an electron as both particles and waves at the same time.