Topic 2: Atomic Structure Flashcards
Rutherfords Experiment
- Proved atoms had a nucleus as some alpha particles were deflected
Relative Atomic Mass Definition
The average mass of all isotopes of an element relative to carbon 12
Five Stages of Mass Spectrometry (in order)
- Vaporization
- Ionization
- Acceleration
- Deflection
- Detection
Vaporization (Mass Spectrometry)
Vaporized sample containing atoms or molecules of interest are injected into the instrument allowing individual atoms to be analyzed
Ionization (Mass Spectrometry)
Atoms are bombarded with a stream of high energy electrons, knocking off valence electrons
Acceleration (Mass Spectrometry)
Cations are attracted by the negatively charged plates and accelerated by the electric field
Deflection (Mass Spectrometry)
The ions are deflected by an external magnetic field proportional to the charge/mass ratio (m/z)
Detection (Mass Spectrometry)
Ions of a particular mass/charge ratio are detected and a signal is sent to a recorder; the strength of the signal is a measure of the number of ions
Charge/Mass Ratio
- The lower the m/z ratio, the greater the deflection
- (32)S(2+), 32/2 = 2
Continuous Spectrum
When sun light on an incandescent light bulb passes through a prism then one will observe a rainbow
Line/Emission Spectrum
- When heat of electricity is applied to an atom its electrons are excited and jump to higher energy levels
- When the electrons return to lower energy levels, they emit energy in the form of light (photon)
Colour and Amount of Energy
- Red has the least amount of energy
- Purple has the most amount of energy
Hydrogen Spectrum
- Red, n=3 to n=2
- Cyan, n=4 to n=2
- Blue, n=5 to n=2
- Violet, n=6 to n=2
Planck’s Equation
C = λf, speed of light = (wavelength)(frequency)
E = hf, energy = (planck’s constant)(frequency)
Basis of Bohr’s Model
- The higher the energy level the farther away the electron is from the nucleus
- Electrons are quantized, meaning they can only occur in one energy level or another
- The ground state is the energy level an electron normally occupies
Electron Transition
- An election moves to a higher energy level when a photon (form of light energy) is absorbed
- The electron moves to a lower energy level when photon is emitted
Types of Series in Electron Transition
- Balmer series
- Lyman series
- Paschen series
Balmer Series
Visible light region, resulted from electron transition from higher levels down to n=2)
Lyman Series
Ultraviolet light, produced when electrons drop to the first energy level
Paschen Series
Infrared, produces when electrons drop to the third energy level
Line of Convergence
- The separate lines in a series become closer together as their wavelength decreases
- At these high energy, the lines form a continuum
- The start of the continuum, beyond which separate lines cannot be distinguish is called the convergence limit
Heisenberg Uncertainty Principal
States its impossible to define the exact position of an electron
Schrodinger Model
Developed a more sophisticated model as electrons behave like waves in 3 dimensional spaces
Sub-Level
- Sub-levels contain a fixed number of orbitals
- Each orbital can hold 2 electrons
S Sub-Level
Spherical shop with 1 orbital, holding 2 electrons
