Quantum Theory and the Electronic Structure of Atoms Flashcards
Electrons
How Light Energy is Determined?
- wavelength
- frequency
- energy
Electrons
When are wavelengths seen?
When electrons return to ground level
Electrons
Planck’s Constant
- h
- 6.022E-34 Jᐧs
- Slope of E∝V
Properties of Light
What is Electromagnetic Radiation
- EMR
- Properties of Light
Properties of Light
Wavelength
- Length of one wave
- Meters
- 𝝀
Properties of Light
Frequency
- Number of wavelengths(or cycles) per sec passing a point
- 1/s or s^-1 or Hz
- 𝛎
Properties of Light
Speed of Light
- 2.998E8 m/s
- c
Properties of light
Amplitude
- Higher is Brighter while Lower is darker
Properties of Light
Equations for Energy, and Light Parts
- c = 𝝀 ᐧ 𝛎
- E = h𝛎
- E = hᐧc/𝝀
* Is the Energy of 1 photon
What are Photons?
Particle side of electrons
Planck’s Work
What does delocalized mean?
the electron is not with a certain atom or nucleus
Planck’s Work
What is a Quantum
A packet of Energy for an electron to jump to the next electron level
Einstein’s work
What is Photon Energy related to?
- Ephoton ∝ 𝛎
- Ephoton ∝ 1/𝝀
PES equation
Ephoton = KEelectron + BEelectron
- BE = binding energy
Bohr’s Work
Energy Equation to move electron in Hydrogen
NOT IMPORTANT FOR TEST
ΔE = (-2.178E-18 J )((1/nf^2) - (1/ni^2))
de Broglie’s Work
Mass Equation
h/(𝝀v)
Quantum Numbers
Types
- n = Priniciple quantum number
- l = Angular quantum number
- m = Magnetic quantum number
- ms = Magnetic Spin
Quantum Numbers
Nodes
No possibility for electron(white shell)
Quantum Numbers
Principle Quantum Number
- n
- Integral Number
- Related to size and energy of orbital
- Corresponds to Bohr’s energy level
- More n
1. Increased Orbital
2. Increased distance of electron from orbital
3. Increased Energy
4. Decreased energy between orbitals
Quantum Numbers
Angular Momentum Quantum Number
- Shape
- l = 0–> (n-1) for each n val
- if n=3, possible orbitals s(0)–>d(2)
Quantum Numbers
Magnetic Quantum Number
- m
- integers specifying orbital orinetation
- Values are from -l←→+ l
- Includes 0
- Example: l = 2: m=-2,-1,0,1,2 ⇒ 5 orbitals
Quantum Numbers
Electron Spin
- Up = + .5 spin
- Down = - .5 spin
Quantum Numbers
Difference between H and Multielectron atoms
- H = subshell E levels that are degenerate(same n-int at same level)
- Multi = lower orbital energies
* Subshell of prinicple shell at different energies
Quantum Numbers
Rules for Electron Placement
- Pauli Exclusion Principle
* No 2 electrons in atom has same 4 quantum numbers
* electrons in 1/2 filled orbitals have parallel spins - Hund’s Rule
* One electron for each orbital before doubling up - Aufbau Principle
* Electron occupy lowest energy level possible
Electron Configuration
How do you write Electron Configuration
- Removal Order
- Ex) Se: [Ar] 3d^10 4s^2 4p^4
Electron Configuration
Valence Electrons
- Outermost principle shell
- Usually S or S and P
Electron Configuration
Shortcut using Noble Gases
- Can use closest previous noble gas in brackets then build the rest of the electron config from there
- Cannot use this for noble gas in ground state
Electron Configurations
Electron Configuration Exceptions
- Cr: [Ar] 3d^5 4s^1 (Same with Mo)
- Cu: [Ar]3d^10 4s^1(Same rule with Au and Ag)
Ionization Energy
What is Ionization Energy
- Minimum Energy neede to remove electron from atom or ion
Ionization Energy
Ionization Energy Requirements
- Gas State
- Endothermic
- Valence electron first
- Successive removed for 2nd etc IEs
PES
Why are X-rays used?
- Can dislodge electrons
PES
Relation between BE and KE
- Inversely Related
Magnetic Properties of electrons
Paramagnetic
- one or more unpaired electron
- attracted by a magnetic field
Magnetic Properties of electrons
Diamagnetic
- Paired electrons
- opposite spins that cancel out their magnetic fields
- Are not attracted to outside magnetic field
Magnetic Properties of electrons
How are they detected
- weighing a substance in the presence of a magnetic field
Periodic Trends
Atomic Radius
- Is the distance form the nucleus to the valence electrons
- Across Period: decreased radius due to higher effective nuclear charge
- Down Group: Increased radius due to higher n and a greater distance from the nucleus(higher n ==> higher V)
Periodic Trends
Cations
- Decreased sized compared to original
- decreased electrons with same proton number
Periodic Trends
Anions
- Increased size
- Increased electrons with same proton number
- Electron - Electron Repulsion
Ionization Energy
What is the first IE equal to?
- Binding Energy
Electron Affinity
Electron Affinity
- Energy released when neutral atoms gain electrons
1. Needs to be in gas state
2. M(g) + 1 electron –> M^1-(g) + EA etc(Successive) - Exothermic
- Increased energy leads to Increased negative EA
- Outer electrons are delocalized: can move around which leads to sea of electrons
Periodic Trends
Metallic
- Most = Bottom Left
- Least = Top Right
