The Development of A New Atomic Model Ch. 4.1

Properties of Light Acts like a wave Electromagnetic radiation-wavelike energy traveling through space X-Rays, ultraviolet light, infrared light, radio waves, etc Electromagnetic Spectrum- organized list of all forms of electromagnetic radiation All forms travel 3.00 x 108 m/s in a vacuum

Properties of Light Wavelength Frequency λ Distance from crest to crest(or tough to trough) of corresponding waves SI Unit: m, cm, or nm ν # of waves that pass a given point in a specific time SI Unit: Hz

Photoelectric Effect Emission of electrons from a metal when light shines on the metal

Light as a Particle Quanta Photon Quantum of energy is the minimum amount of energy that can be lost or gained by an atom E- energy, J h- Plancks Constant 6.626 x 10-34 Js v- frequency, s-1 Photon Particle of electromagnetic radiation having zero mass and carrying a quantum energy

The Hydrogen-Atom Line Emission Spectrum Ground State Excited State Lowest energy state of an atom Atom has a higher potential energy than it does in ground state Gives off light Moving from excited back to ground state

The Hydrogen-Atom Line Emission Spectrum Continuous Spectrum Narrow beam of light, when passing through a prism Emission of a continuous range of frequencies of electromagnetic radiation

Bohr’s Model of the Hydrogen Atom Emission Electron falls to a lower energy level Photon is emitted Absorption Electron jumps from lower to higher energy level Energy must be added

The Quantum Model of the Atom Ch 4.2

Electrons as Waves Diffraction Interference Bending of a wave as it passes through a small object Waves overlap Different areas have Reduced energy Increased energy

Heisenberg Principle It is impossible to determine simultaneously both the position and the velocity of an electron of any other particle

Schrodinger Wave Equation Quantum Theory Describes mathematically the wave properties of electrons and other very small particles Gives the probability of finding an electron in a given orbital 3 dimensional region around the nucleus that indicates the probable location of an electron

Atomic Orbital's and Quantum Numbers Specifies the properties of atomic orbital's and the properties of electrons in orbital's 1st 3 Numbers Indicate main energy level, shape and orientation of orbital 4th Number “Spin” number describes the fundamental state of the electron that occupies the orbital

Atomic Orbital's and Quantum Numbers Principle Quantum Number Symbol- n Indicates main energy level occupied by electron Positive integers only 1,2,3, etc As n increases, distance from nucleus increases Electrons can have the same value Same shell Total orbital's in a shell(main energy level n2

Atomic Orbital's and Quantum Numbers Angular Momentum Quantum Number Sublevels Orbital's of different shapes exist for a given value of n Symbol- l Indicates the shape of the orbital Value n-1; can be zero or positive integers

Atomic Orbital's and Quantum Numbers Angular Momentum Quantum Number s orbital Spherical p orbital Dumbbell shape d & f orbital's More complex n=1 S orbital n=2 s & p orbitals n=3 s, p, & d orbitals n=4 s, p, d & f orbitals

Atomic Orbital's and Quantum Numbers Magnetic Quantum Number Symbol- m Indicates the orientation of an orbital around the nucleus Value Whole numbers, including zero; -l to +l

Atomic Orbital's and Quantum Numbers Spin Quantum Number Only 2 Values +1/2 and -1/2 Indicates the 2 spin states of an electron in an orbital Single Orbit Max of 2 electrons Must have opposite spin states

Electron Configuration Ch 4.3

Electron Configuration Arrangement of electrons in an atom Unique for each element Ground State Electron Configuration Lowest energy arrangement of electrons for each element

Rules for Electron Configuration Aufbau Principle Electrons occupy the lowest energy orbital that can receive it

Rules for Electron Configuration Pauli Exclusion Principle No two electrons in the same atom can have the same set of four quantum numbers Arrows represent different spin states

Rules for Electron Configuration Hund’s Rule Orbital's of equal energy are each occupies by one electron before any orbital is occupied by a second electrons All electrons in singly occupied orbital's must have the same spin state

Representing Electron Configurations Orbital Notation Electron Configuration Notation Unoccupied orbital ___ Orbital with 1 electron Orbital with 2 electrons Quantum # and Sublevel underneath Eliminates lines and arrows Uses superscripts 1s22s22p6

Practice pg 113

2nd Period Elements Highest Occupied Energy Level Electron contained main energy level with the highest principle quantum number Inner Shell Electrons Electrons no in the highest occupied energy level

3rd Period Elements Shorthand Notation Noble Gas Configuration 1st 10 electrons in an atom have the same configuration as Neon Noble Gas Configuration Outer main energy level occupied by 8 electrons (most cases)

4th & 5th Period Elements

Practice pg 120

Practice pg 121

Practice pg 122