Electron Configuration The way electrons are arranged around the nucleus.
Quantum Mechanical Model 1920’s Werner Heisenberg (Uncertainty Principle) Louis de Broglie (electron has wave properties) Erwin Schrodinger (mathematical equations using probability, quantum numbers)
Heisenberg uncertainty principle it is impossible to determine simultaneously both the position and velocity of an electron or any other particle with any great degree of accuracy or certainty.
Erwin Schrodinger Formulated equation that describes behavior and energies of subatomic particles. Incorporates both particle and wave behavior in terms of wave function: is proportional to the probability of finding an electron. Leads to Quantum Mechanics: we cannot pinpoint an electron in an atom but we can define the region where electrons can be in a particular time……… called a Probability map….a 3-dimensional area in space called an ORBITAL
Principal Quantum Number, n Indicates main energy levels n = 1, 2, 3, 4… Each main energy level has sub-levels
-Pauli Exclusion Principle (Wolfgang Pauli, Austria, 1900-1958) -Electron Spin Quantum Number An orbital can hold only two electrons and they must have opposite spin. Electron Spin Quantum Number (m s ): +1/2, -1/2
Hund’s Rule In a set of orbitals, the electrons will fill the orbitals in a way that would give the maximum number of parallel spins (maximum number of unpaired electrons). Analogy: Students could fill each seat of a school bus, one person at a time, before doubling up.
Standard Notation of Fluorine Main Energy Level Numbers 1, 2, 2 Sublevels Number of electrons in the sub level 2,2,5 1s 2 2s 2 2p 5
Shorthand Notation Use the last noble gas that is located in the periodic table right before the element. Write the symbol of the noble gas in brackets. Write the remaining configuration after the brackets. Ex: Fluorine: [He] 2s 2 2p 5