Quantum Model of the Atom Electrons in Atoms

A. Electrons as Waves zLouis de Broglie (1924) yApplied wave-particle theory to e - ye - exhibit wave properties QUANTIZED WAVELENGTHS

A. Electrons as Waves QUANTIZED WAVELENGTHS

A. Electrons as Waves EVIDENCE: DIFFRACTION PATTERNS ELECTRONS VISIBLE LIGHT

B. Quantum Mechanics zHeisenberg Uncertainty Principle yImpossible to know both the velocity and position of an electron at the same time

B. Quantum Mechanics zSchrödinger Wave Equation (1926) yfinite # of solutions  quantized energy levels ydefines probability of finding an e -

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

C. Quantum Numbers UPPER LEVEL zFour Quantum Numbers: ySpecify the “address” of each electron in an atom

C. Quantum Numbers 1. Principal Quantum Number ( n ) yEnergy level ySize of the orbital yn 2 = # of orbitals in the energy level

C. Quantum Numbers s p d f 2. Angular Momentum Quantum # ( l ) yEnergy sublevel yShape of the orbital

C. Quantum Numbers zn=# of sublevels per level zn 2 =# of orbitals per level zSublevel sets: 1 s, 3 p, 5 d, 7 f

C. Quantum Numbers 3. Magnetic Quantum Number ( m l ) yOrientation of orbital  Specifies the exact orbital within each sublevel

C. Quantum Numbers pxpx pypy pzpz

zOrbitals combine to form a spherical shape. 2s 2p z 2p y 2p x

C. Quantum Numbers 4. Spin Quantum Number ( m s ) yElectron spin  +½ or -½ yAn orbital can hold 2 electrons that spin in opposite directions.

C. Quantum Numbers 1. Principal #  2. Ang. Mom. #  3. Magnetic #  4. Spin #  energy level sublevel (s,p,d,f) orbital electron zPauli Exclusion Principle yNo two electrons in an atom can have the same 4 quantum numbers. yEach e - has a unique “address”:

Feeling overwhelmed? Read Section 4-2!