Electron ConfigurationChemistry IMr. Pena

Bohrs Atom Model-Confines electrons in shells-Electrons loses energy due to movement.-Electrons can be in certain levels depending of the energy they have.-The region where we can find the electron with high probability is called the orbital.

Nature of the electron-Thompsons work show that e- behave like particles.-In 1924, Louis de Broglie states that e- behave like waves based on Bohrs model.-This was explained in the electromagnetic spectrum.

Electromagnetic SpectrumThe frequency is mathematicaly related to the wavelenght:c=vWhere c=speed of light (3.0 x 108 m/s)= wavelenght v= frequency

Electromagnetic SpectrumAll the frequencies or wavelenghts of electric radiation.

Electromagnetic Spectrum-The movement of electrons produced light when received and release energy.-In 1905, Albert Einstein proposed that light have properties of light and waves.

Light Emission

Light EmissionElectron in lowest possible energy is in ground state.Electron that gains energy move to excited state.Electron release energy as go back to ground state.

Light EmissionE1=Energy in ground stateE2=Energy in excited stated.Overall energy= E1-E2

Quantum Numbers-Number that specifies the properties of the electrons.

-There are 4 quantum numbers: n, , m and ms

Quantum Numbersn= level number (n=1 thru 7). (n-1)= Shape and type of orbitals=0p=1d=2f= 3m (from ,0,+)=Magnetic quantum numberms= Magnetic spin. Only have two possible numbers (+1/2 and -1/2)

Electron configurations-Arrangements of electrons in an atom.-Each orbital can have only 2 electrons and with different quantum numbers. This is known as Pauli exclusion principle.

Electron configuration Types and shapes of orbitals

Electron configuration Aufbau principle -Electron fill lowest energy levels first.Ex. 1s

Electron configuration NotationsThere are 3 notations:1) Long notation or electron configuration1s22s22p6

2) Orbital Notation

Electron configuration 3) Shorthand Notation or Noble Gas configuration.[Ne]3s23p4

Electron configuration Hunds Rule -For atoms in ground state, the number of unpaired electrons is the maximum possible and have the same spin.

Electron configuration Orbital Filling Order (Diagonal Rule)

Electron configuration Example What is the electron configuration of an element with atomic number of 9 (Z=9)An element with z=9 is Fluorine.We start with the less energy level and orbital, so then is 1s22s22p5. The orbital notation will be then