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Atomic Theory Quantum and Electron Configuration (Chapter 4)

King Low Heywood Thomas School
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Atom
Basic unit of matter (Electrically Neutral)
Subatomic Particles
Electrons (-) Protons (+) and Neutrons (No charge)
(They are not the basic unit of matter since alone they cant make anything but together they create matter)
(Democritus) Discontinuous Theory of Matter
There is a limit to the amount of times that matter could be divided. He named the smallest unit that could not be broken down any further atomos meaning indivisible.
(Aristotle) Continuos Theory of Matter
The division of matter was limitless therefore rejected the atom proposed by Democritus.
(Aristotle) 4 Elements
Instead of the Continuos Theory of Matter, Aristotle believed that all matter was a combination of earth, air, fire and water. (Due to his popularity, the atom was overlooked for 2000 years)
(Daltons) First Postulate
Elements are compromised of particles called Atoms (Ex: Element Ag is made of Ag atoms)
(Daltons) Second Postulate
Atom of an element are the same in regard to mass and properties (Ex: All Ag atoms have the same properties and mass and all N atoms have the same properties and mass)
(Daltons) Third Postulate
Compound are formed by the joining of atoms of two or more elements and always combine int he same ratio (Ex: H and Cl in HCl and O and O in O2)
(Daltons) Forth Postulate
Chemical reactions is a rearranged of atoms. Atoms are conserved (Ex: 4k+ 02 -> 2k20)
(Thomson) Subatomic Particles
Studied voltage through a vacuum glass tube called a Cathode Ray Tube
(Thomson) Experiment Result 1
The mass of rays were about 1000x less than that of lightest atom (H)
(Thomson) Experiment Result 2
The mass the rays were always the same no matter what type of metal was used to run the voltage
(Thomson) Experiment Result 3
The rays were attracted to a positive charge and deflected by negative one
(Thomson) Experiment Result 4
The rays were actually subatomic particles called electrons originating from the metal
(Thomson) Final Result Atom Model
He created the plum pudding model of the atom (Electrons distributed throughout a uniform positive charge)
(Rutherford) Nucleus Expirement
Studied the effects of positive charge radiation hitting gold atoms
(Rutherford) Nucleus Result 1
Positive charge was localized in the center of the atom called the Nucleus
(Rutherford) Nucleus Result 2
Atomic mass is concentrated in in the Nucleus
(Rutherford) Nucleus Result 3
Electron travel around the nucleus
(Rutherford) Nucleus Result 4
Rest of the atom was mostly empty space
Electromagnetic Radiation (EMR)
How energy is propagated through space
Speed of Light
3.0x10^8 m/s
Wave
Repeating change, or oscillation in matter or a field
Wavelength, λ
The distance between two consecutive points on a wave. (Units = m)
Frequency
the rate at which a wavelength passes a point in space. (Units = s or /s, s1-, or hertz(Hz))
Calculating Wavelength and Frequency
C = λf (C= Light) (To find λ just use C(Light)/f(Frequency) and to find f just use C(Light)/λ(Wavelength)
Electromagnetic Spectrum
Is the range of all possible frequencies of electromagnetic radiation
Electromagnetic Spectrum 2
Because speed of EMR is constant, smaller wavelength = greater frequency = great energy
Types of Spectrums (Longest to shortest)
Radio, Microwave, Infrared, Visible (Red, Yellow, Green, Blue, Purple), Ultraviolet, X-ray, Gamma Ray
Thermodynamic equilibrium relating to EMR
Matter contains charge particles that move due to KE. To establish TE they must release EMR waves.
Blackbody radiation
THe EMR realease during thermodynamic equilibrium
Frequency of EMR
Directly related to temperature
Continuos Spectrum
Heated dense objects contain high vibrating electrons which result in production of varying frequencies. (For this reason the spectrum released from blackbody is hot enough to produce visible light appears as Continuos Spectrum)
Study how energy is divided amongst the varying electromagnetic frequencies
Scientist studied EMR produced inside a black cavity when it was heated up.
Prior to Study of dividing of electromagnetic frequencies (1)
All frequencies where possible to create
Prior to Study of dividing of electromagnetic frequencies (2)
Number of standing waves produced increased with frequency
Prior to Study of dividing of electromagnetic frequencies (3)
All added energy was spread out evenly amongst all standing waves- Energy was said to be continuous
Prior to Study of dividing of electromagnetic frequencies (4)
The amount of energy produced at a given frequency range should be proportional to the number of standing waves in that range.
EMR Range
The amount of radiated energy id not increase with increasing frequency, but began to sharply decrease after visible light
Planck (1)
Waves at higher frequency were actually less likely to be created, because an atom can not produce more energy then it has. (So, the probability of finding frequencies in the UV and greater range decreased dramatically)
Planck (2)
Plank postulated that the energy was not continuous (All standing waves could not posses any amount of energy) (Waves of certain frequency could only hold fixed amounts of energy) (He called them quantum)
Planks Equation
E = hf (E= Energy of the EMR wave quantized) (F= Frequency of the quantum of energy) (Planks constat = 6.626x10-34J•S)
Atomic Emission Spectrum Produced
Heated high density object(black body) creates a Continuous Spectrum and Heated low density Elements create an Atomic Emission Line Spectrum
(Bohr) Planetary Model
Proposed that electrons travel in fixed paths called orbits around the nucleus
(Bohr) Planetary Model 2
Electrons energy is dependent on which orbit it is located in (Closer to nucleus = Less energy and farther = greater energy)
Aufbua Principle
States that electrons arrange themselves in the lowest energy state. This low energy state is known as the ground state
(Aufbua Principle) Law of Conservation of Energy
Due to the Law of Conservation of Energy, for electrons to fall back to the original stable ground state, electrons must release the same amount of energy that was absorbed
(Lous de Broglie) Partile- Wave Duality
That electrons act as both particles and waves
(Lous de Broglie) Orbits
De Brogile showed that electrons travel in orbits as standing waves rather then in circles proposed by Bohr
Electron pulled in Nucleus
Cause electron (-) and nucleus (+) it was thought that the electron wold spiral into the nucleus and destroy the atom (Not the case)
Electron pulled in Nucleus 2
Thought momentum of electron spiraling is what offset the pull of positive nucleus inward keeping electron fixed distance from nucleus
Electron pulled in Nucleus 3
Electron pulled in Nucleus 2 not the case found that accelerated charged particles lose energy by emitting EMR. Thus, the electron would definitely spiral into the nucleus (Stability cant be explained) (Idea of fixed ornits must be wrong)
(Schrodinger) Electron path
Mathematically determined that electrons do not travel in a classical circular waves around the nucleus in orbits
(Schrodinger) Electron path 2
Scientists could only calculate where the probability of finding electrons was the greatest around the nucleus- this is called a wave function and exhibits three dimensions.
Orbitals
Therefore, rather then traveling in orbits, electrons could appear in a one of many three dimensional wave functions called orbitals (Obitals- regions around the nucleus where the there is a greater probability of finding electrons)
Types of Orbitals
s orbital (circle) p orbital (figure 8) and d orbital (random)
(Heisenberg) Heisenberg's Uncertainty Principle
Stated that is mathematically impossible to know exactly both the position and momentum of a particle
(Heisenberg) Heisenberg's Uncertainty Principle (Particles and larger objects)
Larger objects have smaller wave function -> uncertainty is low -> movement appears consistent and ruin in a predictable path

Sub-Atomic articles possess a large wave function -> Uncertainty high 0> movement is not consistent and does not run in predictable path
Electron Cloud Model
(Used current day) Different Orbitals together appear as a cloud of probability where electrons can be found around the nucleus
Magnetic quantum number
Each Sublevel is also assigned a magnetic quantum number (mℓ), which states how many orbitals are in each Sublevel (s=1, p=3, d=5, f=7)
Number of electrons on magnetic quantum number
s= 1 = 2 p = 3 = 6 d = 5 = 10 f = 7 = 14
Principle quantum number
AKA Distance rom nucleus or energy level
Angular momentum quantum number
AKA-Shape or sublevel
Order in electron congif
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
Hunds rule
Electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals
Electron Configuration
Written out version of orbital diagram
Noble Gas configuration
Take the noble gas before the element you are doing, erase the part of the equation that goes up to that noble gas and then put the extra stuff (So [Ne] 3s2 3p4)
Electron dot structure
Valence electrons is the electron in the highest energy level of the atom (The dot structure takes the highest energy level and takes the exponent, add them and thats how many dots are in it) ([Ne] 3s2 3p4 so S has 6 dots)