The Quantum Model of the Atom

Intro to Quantum Mechanics

Electrons as Waves Louis de Broglie (1924) –Applied wave-particle theory to electrons –Electrons exhibit wave properties QUANTIZED WAVELENGTHS

Quantum Mechanics Heisenberg Uncertainty Principle –Impossible to know both the velocity and position of an electron at the same time

Quantum Mechanics Schrödinger Wave Equation (1926) –Finite number of solutions  quantized energy levels –Defines probability of finding an electrons

Quantum Mechanics Radial Distribution Curve Orbital Orbital (“electron cloud”) –Region in space where there is 90% probability of finding an e -

Electron Structure Electrons arranged into energy levels. –Names like “n=1” and “n=2”. n = 1 n = 2 n = 3 n = 4 Nucleus More Energy

Principal Energy Levels Energy level (n) Maximum Number of Electrons

Electron Structure Energy levels are divided into sublevels. –Sublevels within an energy level have similar energy.

s, p, d, and f orbitals

Electron Structure Sublevels are made of orbitals. –Each orbital can hold up to 2 electrons. SublevelOrbitalsElectrons S12 P36 D510 F714

Valence Electrons Valence electrons – Electrons in an atom’s highest-numbered energy level. You can tell how many valence electrons any atom should have by its position in the periodic table variable

Lewis Dot Diagrams Lewis Dot Diagram – shows the valence electrons of an atom. –First 2 electrons paired on one side. –Remaining electrons are placed on other sides. –Should never have more than 8 dots.

Lewis Dot Diagrams Here are the Lewis diagrams for 8 elements, which have 1 – 8 valence electrons. LiBe B C N O F Ne