Spin-Orbit Effect In addition to its motion about the nucleus, an electron also has an intrinsic angular momentum called “spin” similar to the earth moving.

Slides:



Advertisements
Similar presentations
CHAPTER 9 Beyond Hydrogen Atom
Advertisements

There are a total of n subshells, each specified by an angular momentum quantum number, and having an angular momentum of The allowed energy levels are.
EXAM #3 HAS BEEN MOVED TO MONDAY, NOVEMBER 9 TH Bring a Periodic Table to class this week November 2, 2009.
The Quantum Mechanical Picture of the Atom
1 8.1Atomic Structure and the Periodic Table 8.2Total Angular Momentum 8.3Anomalous Zeeman Effect Atomic Physics CHAPTER 8 Atomic Physics What distinguished.
LECTURE 22 More Atom Building PHYSICS 420 SPRING 2006 Dennis Papadopoulos.
1 8.1Atomic Structure and the Periodic Table 8.2Total Angular Momentum 8.3Anomalous Zeeman Effect Atomic Physics CHAPTER 8 Atomic Physics What distinguished.
Quantum numbers.
Quantum Numbers How to find your atom’s address in the Periodic Table Hotel.
Arrangement of Electrons in Atoms
Chapter 41 Atomic Structure
ELECTRON CONFIGURATION. Electron Configuration  The way electrons are arranged around the nucleus.
Vector coupling of angular momentum. Total Angular Momentum L, L z, S, S z J and J z are quantized Orbital angular momentumSpin angular momentum Total.
Quantum Numbers Activity. Quantum Numbers Quantum numbers tell us properties of the atomic orbitals, and electrons, in an atom. Like giving each electron.
MULTIELECTRON ATOMS l ELECTRON SPIN: Electron has intrinsic angular momentum - “spin”; it behaves as if it were “spinning”, i.e. rotating around its axis.
Electron Location Part II. Principal quantum number (n) - describes the SIZE of the orbital or ENERGY LEVEL of the atom. Angular quantum number (l) or.
Lecture VIII Hydrogen Atom and Many Electron Atoms dr hab. Ewa Popko.
Chapter 5 Quantum Numbers Part 2. The Third Quantum Number The third quantum number identifies the orbital that the electron is in.
Quantum Numbers Each electron in an atom has a unique set of 4 quantum numbers which describe it.  Principal quantum number  Angular momentum quantum.
THE TRUE MYSTERY OF THE WORLD IS THE VISIBLE, NOT THE INVISIBLE. - Oscar Wilde -
Spin Electronic charge in motion - A current loop behaves as a magnetic dipole and has a magnetic moment. - Note the current direction is opposite to the.
Electromagnetic Spectrum Atomic Emission Spectrum.
Atomic Structure. Electron Configurations The way electrons are arranged around the nucleus.
Writing Electron Configuration. Quantum Numbers Quantum numbers define the location of electrons in an atomic orbital. This helps us understand why different.
 Electron Configuration is the way electrons are arranged around the nucleus.
Labeling Electrons in Atoms. 2) Three numbers give the location of the electrons. The forth describes the spin of the electron. 3) The first quantum number,
PART 2 QUANTUM THEORY.
Quantum-Mechanical View of Atoms
Germano Maioli Penello Chapter 7 Magnetism in the localised electron model Presentation based on the book Magnetism: Fundamentals, Damien Gignoux & Michel.
Wednesday, October 21 st, 2015 Bohr Model of the Atom.
Protons, Neutrons, and Electrons
Electronic States of Atoms Quantum numbers for electronsQuantum numbers for many-electron atoms l: orbital angular momentum quantumL: orbital angular.
Electron Configuration. Objectives Describe the relationship between orbitals and energy levels for the electrons of an atom Describe the relationship.
Quantum Numbers n, l, m, and s – Used to describe an electron in an atom Probable location n – Principal Quantum Number – Represents main energy level.
Electron Location: Part III Electron Configuration.
Energy Level of the Atom Based on the Bohr & The Wave Mechanical Model.
Protons and Neutrons form a nucleus.. Electrons Atomic Number and Mass Number Atomic Number Is the Number of Protons of the Nucleus.
Electron Orbitals Cartoon courtesy of lab-initio.com.
Quantum Mechanical Model. Quantum Numbers (n, l, m l, m s ) n = ____________ Quantum Number It has whole number values (1, 2, 3, …) An n increases, the.
Ch. 4.3 Electron Configuration. POINT > Define electron configuration POINT > Explain the Aufbau principle POINT > Explain the Pauli exclusion principle.
Electron Configuration Chemistry Mrs. Coyle. Electron Configuration The way electrons are arranged around the nucleus.
7. Quantum-Mechanical View of Atoms
ELECTRON CONFIGURATIONS
Quantum Mechanical Model
Electron Configurations
What value of wavelength is associated with the Lyman series for {image} {image} 1. {image}
Spin Quantum Number, ms In the 1920s, it was discovered that two electrons in the same orbital do not have exactly the same energy. The “spin” of an electron.
Quantum Numbers AP Chemistry: Chapter 7.
Orbital Diagrams
Unit 1:Atomic Structure Part 2
Electron Orbitals Heisenberg 1. The ____________ ______________ principle states that it is impossible to determine simultaneously both the position and.
Quantum Theory.
Electron Configuration
Electron Orbitals Cartoon courtesy of lab-initio.com.
Quantum Mechanical Model of the Atom
Orbitals and Quantum Numbers
Quantum Numbers Part Two.
Quantum Theory.
Electronic structure in atoms
Electromagnetic Spectrum Atomic Emission Spectrum.
Quantum Theory.
Atomic Orbitals and Electron Arrangement
How can you express the arrangement of electrons in atoms through electron configurations? In an atom, electrons and the nucleus interact to make the most.
Quantum Mechanical Model
The Spin Quantum Number
7. Quantum-Mechanical View of Atoms
Quantum Theory.
2.4- Quantum Mechanical Model
Electron Orbitals Cartoon courtesy of lab-initio.com.
QM2 Concept test 5.1 There are three distinguishable particles with the same mass in a one dimensional infinite square well. The single particle stationary.
Presentation transcript:

Spin-Orbit Effect In addition to its motion about the nucleus, an electron also has an intrinsic angular momentum called “spin” similar to the earth moving about the sun and spinning on its axis orbital angular momentum L = r x p spin angular momentum S cannot be written in terms of coordinates total angular momentum of the electron is J = L + S if L // S, then J=L+S if L antiparallel S, then J=L-S in quantum mechanics angular momentum is quantized and has magnitude given by Electrons have spin s=1/2 and are fermions

Spin-Orbit Effect Consider a state with l=1 and s=1/2. What are the possible values of j j= 1-1/2=1/2 and j=1+1/2 = 3/2 Quantum states with the same values of n and l but different j have small energy differences => fine structure due to spin

Electron moving about a proton with angular momentum L Magnetic field due to apparent motion of charged proton is up When electron spin is up, its magnetic moment is down and energy is higher When electron spin is down, its magnetic moment is up and energy is lower E~ L.S

n=1 l=0 => 1S j=1/2 n=2 l=0,1 => S or P 2S level has j=1/2 2P level has j=1/2 or 3/2 Fine Structure E~ L.S

Periodic Table Atoms with more than one electron cannot be solved exactly assume the Z electrons do not interact with one another but rather only see the nucleus with charge +Z the state of each electron is described by four quantum numbers n, l,m and m s the fourth number, m s =  1/2 is the spin quantum number l = 0, 1, 2, 3, 4, 5, … correspond to s p d f g h Pauli principle: no two electrons can have the same set of values of n, l,m and m s eg. Hydrogen (Z=1) has only one electron lowest energy state has n=1 => l=0 => m=0 and m s =  1/2 1s state

Periodic Table Helium ( Z=2) has two electrons we can put both in the n=1 energy state with l=0 and m=0 but with opposite spin hence total spin is zero, total orbital angular momentum is zero, and total (spin + orbital) angular momentum is zero ==> j=0. Denote as 1s 2 Lithium (Z=3) has three electrons first two as in He but third must go into n=2 level =>l=0 or 1 l=0 has lower energy denote as 1s 2 2s Beryllium (Z=4) has 1s 2 2s 2 electron configuration

Periodic Table An s state (l=0) can hold a maximum of 2 electrons a p state (l=1) can hold a maximum of 6 electrons a d state (l=2) can hold a maximum of 10 electrons in general, 2(2l+1) states neon (Z=10) has ten electrons configuration is 1s 2 2s 2 2p 6 Hund’s rules argon (Z=18) has eighteen electrons configuration is 1s 2 2s 2 2p 6 3s 2 3p 6 1s2s2p Ne3s3p E~ L.S

Periodic table configurations