To describe Rutherford’s model of the atom Objectives To describe Rutherford’s model of the atom To explore the nature of electromagnetic radiation To see how atoms emit light

Rutherford’s Atom – But what are those electrons doing?

How can different colored fireworks be made. Why do we get colors How can different colored fireworks be made? Why do we get colors? Why do different chemicals give us different colors? 

To understand e-s, we study electromagnetic radiation. 2. Energy and Light To understand e-s, we study electromagnetic radiation. GAMMA-prolonged exposure? ROY G. BIV, Micro, Radio

TThe rainbow is more beautiful than the pot of gold.

2. Energy and Light How are the types of light different? Wavelength, λ Energy travels in wave motion. Shorter wavelength, more energy. Spring Demo.

Electromagnetic Radiation One of the ways that energy travels through space. Characteristics: Wavelength ( ) – distance between two peaks or troughs in a wave.  Frequency ( ) – number of waves (cycles) per second that pass a given point in space Speed (c) – speed of light (2.9979×108 m/s) or (3×108 m/s)

How are the types of light different? 2. Energy and Light How are the types of light different? PhET Wave on a String PhET Radio Waves PhET Microwave

Different wavelengths carry different amounts of energy. (Drill Demo) 2. Energy and Light Different wavelengths carry different amounts of energy. (Drill Demo)

3. Emission of Energy by Atoms Atoms can give off light. They first must receive energy and become excited. The energy is released in the form of a photon.

Dual nature of light Double Slit Experiment 2. Energy and Light Energy is mass E = mc2 Dual nature of light Double Slit Experiment Wave vs Photon – packet of energy

2. Energy and Light Dual nature of light- show PhET wave on a string- no end, increase frequency and amplitude until you see the photons as part of the wave…PhET Wave on a String

To describe Rutherford’s model of the atom Objectives Review To describe Rutherford’s model of the atom To explore the nature of electromagnetic radiation To see how atoms emit light Work Session: Page 365 # 1-6

To learn about Bohr’s model of the hydrogen atom Objectives To understand how the emission spectrum of hydrogen demonstrates the quantized nature of energy To learn about Bohr’s model of the hydrogen atom To understand how the electron’s position is represented in the wave mechanical model

Refraction of White Light (Continuous Spectrum)

The Line Spectrum of Hydrogen (Line Spectrum)

Energy of the electron in the hydrogen atom is quantized. WHY? Significance Only certain energies (photons) are allowed for the electron in the hydrogen atom. Energy of the electron in the hydrogen atom is quantized. WHY?

1. The Energy Levels of Hydrogen Atomic states Excited state – atom with excess energy Ground state – atom in the lowest possible state When an H atom absorbs energy from an outside source it enters an excited state.

1. The Energy Levels of Hydrogen Energy level diagram Energy in the photon corresponds to the energy used by the atom to get to the excited state.

1. The Energy Levels of Hydrogen Quantized Energy Levels Since only certain energy changes occur the H atom must contain discrete energy levels.

Bohr’s model of the atom Quantized energy levels Electron moves in a circular orbit Electron jumps between levels by absorbing or emitting photon of a particular wavelength

2. The Bohr Model of the Atom Bohr’s model of the atom was not totally correct. Electrons do not move in a circular orbit.

3. The Wave Mechanical Model of the Atom Orbitals (de Broglie and Schrödinger) Nothing like orbits Probability of finding the electron within a certain 3-D space Darker means higher probability

What happens when electrons lose their energy? Objectives Review What happens when electrons lose their energy? Which has lower energy, 0.5 kg of steak or 0.5 kg of hamburger? Why? Why does metal spark when placed in a microwave? They get Bohr’d Hamburger, ground state

To learn about Bohr’s model of the hydrogen atom Objectives Review To understand how the emission spectrum of hydrogen demonstrates the quantized nature of energy To learn about Bohr’s model of the hydrogen atom To understand how the electron’s position is represented in the wave mechanical model Work Session: Page 370 # 2-6

To learn about the shapes of the s, p and d orbitals Objectives To learn about the shapes of the s, p and d orbitals To review the energy levels and orbitals of the wave mechanical model of the atom To learn about electron spin

Hydrogen has discrete energy levels. Called principal energy levels 1. The Hydrogen Orbitals Hydrogen Energy Levels Hydrogen has discrete energy levels. Called principal energy levels Labeled with whole numbers 1, 2, 3, 4

Each principal energy level is divided into sublevels. 1. The Hydrogen Orbitals Hydrogen Energy Levels Each principal energy level is divided into sublevels. Labeled with numbers and letters (s, p, d, f) Indicate the shape of the orbital

Principal Energy Levels 1 - 8 1. Orbitals Summary Principal Energy Levels 1 - 8 Orbitals 4 - s, p, d, f each with unique shapes Level 1 has 1 orbital (s) Level 2 has 2 orbitals (s, p) Level 3 has 3 orbitals (s, p, d) Level 4 has 4 orbitals (s, p, d, f) Level 5 has 4 orbitals (s, p, d, f) Level 6 has 3 orbitals (s, p, d) Level 7 has 2 orbitals (s, p) Level 8 has 1 orbital (s) symmetry

Each suborbital can hold a max of 2 e-s 1. Orbitals Summary Each orbital (s, p, d, f) can be broken down into suborbitals (sublevels) s - 1 p - 3 d - 5 f – 7 Each suborbital can hold a max of 2 e-s

Orbitals do not have sharp boundaries. 1. The Orbitals Orbitals do not have sharp boundaries.

1. The Orbitals Entanglement Heisenburg Uncertainty Principle- LINK The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa.

1s Orbital

Two Representations of the Hydrogen 1s, 2s, and 3s Orbitals

2px Orbital

2py Orbital

2pz Orbital

The Boundary Surface Representations of All Three 2p Orbitals

3dx2-y2 Orbital

3dxy Orbital

3dxz Orbital

3dyz Orbital

Orbital

The Boundary Surfaces of All of the 3d Orbitals

f suborbitals (7)

Principal Energy Levels 1 - 8 2. Orbitals Summary Principal Energy Levels 1 - 8 Orbitals 4 - s, p, d, f each with unique shapes Level 1 has 1 orbital (s) Level 2 has 2 orbitals (s, p) Level 3 has 3 orbitals (s, p, d) Level 4 has 4 orbitals (s, p, d, f) Level 5 has 4 orbitals (s, p, d, f) Level 6 has 3 orbitals (s, p, d) Level 7 has 2 orbitals (s, p) Level 8 has 1 orbital (s) balance, top

Each suborbital can hold a max of 2 e-s 2. Orbitals Summary Each orbital (s, p, d, f) can be broken down into suborbitals (sublevels) s - 1 p - 3 d - 5 f – 7 Each suborbital can hold a max of 2 e-s How can the orbitals be a volume with 1 e-? Helicopter, laser pointer, lighted top

Why can an H atom have so many orbitals and only 1 electron? 2. The Orbitals Why can an H atom have so many orbitals and only 1 electron? An orbital is a potential space for an electron. Atoms can have many potential orbitals. They are always there, waiting to be used. But not always detectable until an electron gains enough energy to occupy Magician Car Accident Schrödinger’s cat….Lottery Cat put in box- given poisoned food– after a while, it is simultaneously dead and alive—although when we look in, it is either, but not both. Lottery- before you look at the winning numbers, ?? I had an accident with a magician, - he just appeared out of nowhere!

3. The Wave Mechanical Model: Further Development Atoms Beyond Hydrogen The Bohr model was modified because it did not apply to all atoms. Atoms beyond hydrogen have an equal number of protons and electrons. Need one more property to determine how the electrons are arranged Spin – electron spins like a top or like the earth

3. The Wave Mechanical Model: Further Development Atoms Beyond Hydrogen Pauli Exclusion Principle - an atomic suborbital can hold a maximum of 2 electrons and those 2 electrons must have opposite spins to maintain balance ………………. car spin, 1st car

To learn about the shapes of the s, p and d orbitals Objectives Review To learn about the shapes of the s, p and d orbitals To review the energy levels and orbitals of the wave mechanical model of the atom To learn about electron spin Work Session: Page 376 # 2-6

To learn about valence electrons and core electrons Objectives To understand how the principal energy levels fill with electrons in atoms beyond hydrogen To learn about valence electrons and core electrons To learn about the electron configurations of atoms with Z < 18 To understand the general trends in properties in the periodic table

1. Electron Arrangements in the First 18 Atoms H atom (Descriptive Notation) Electron configuration – electron arrangement – 1s1 Orbital diagram – orbital is a box grouped by sublevel containing arrow(s) to represent electrons

1. Electron Arrangements in the First 18 Atoms He atom Electron configuration– 1s2 Orbital diagram

1. Electron Arrangements in the First 18 Atoms Li atom Electron configuration– 1s2 2s1 Orbital diagram

Orbital Energies

1. Electron Arrangements in the First 18 Atoms Be atom – 4 e-s (1s22s22p63s23p6) 1s22s2 ______ ______ ______ ______ ______ ______ ______ ______ ______ 1s 2s 2p 3s 3p

1. Electron Arrangements in the First 18 Atoms B atom – 5 e-s (1s22s22p63s23p6) 1s22s22p1 ______ ______ ______ ______ ______ ______ ______ ______ ______ 1s 2s 2p 3s 3p

1. Electron Arrangements in the First 18 Atoms C atom – 6 e-s (1s22s22p63s23p6) 1s22s22p2 * When filling in the orbital diagram, start with the lowest energy level. Work up through each sublevel, being sure to have opposite spins for paired electrons. All suborbitals must contain one e- before any suborbital can be completely filled (p suborbitals). ______ ______ ______ ______ ______ ______ ______ ______ ______ 1s 2s 2p 3s 3p

1. Electron Arrangements in the First 18 Atoms Draw the electron configuration and orbital diagram for: N O F Ne Al P S Cl ______ ______ ______ ______ ______ ______ ______ ______ ______ 1s 2s 2p 3s 3p

1. Electron Arrangements in the First 18 Atoms Draw the electron configuration for: N 1s22s22p3 1s22s2p3 O 1s22s22p4 1s22s2p4 F 1s22s22p5 1s22s2p5 Ne 1s22s22p6 1s22s2p6 Al [Ne] 3s2p1 P [Ne] 3s2p3 S [Ne] 3s2p4 Cl [Ne] 3s2p5

1. Electron Arrangements in the First 18 Atoms 1s22s22p63s23p6 Don’t have to memorize! Properties of families related to valence configuration K [Ar] you might think 3d1, however, properties hint to 4s1 Ca [Ar] you might think 3d2, however, properties hint to 4s2 Less predictability with larger atoms-less F(mag)

1. Electron Arrangements in the First 18 Atoms Classifying Electrons Valence electrons – electrons in the outermost (highest) principal energy level of an atom (designated by group Roman # I - VIII) Core electrons – inner electrons Elements with the same valence electron arrangement show very similar chemical behavior.

2. Electron Configurations and the Periodic Table 1s 2s 2p 3s Li ______ ______ ______ ______ ______ ______ Na ______ ______ ______ ______ ______ ______ Notice the pattern in the valence shell. Notice the energy level and the row on the periodic table. Notice the ionic charge that these make.

2. Electron Configurations and the Periodic Table 1s 2s 2p Cl ______ ______ ______ ______ ______ ______ ______ ______ ______ 1s 2s 2p 3s 3p Notice the pattern in the valence shell, the energy level and the row on the periodic table, and the ionic charge that these make. F ______ ______ ______ ______ ______ ______ (EXCITED) 1s 2s 2p 3s

2. Electron Configurations and the Periodic Table Look at electron configurations for K through Kr Cr and Cu have non-patternistic e- configurations Transition Elements Larger atomic radii have more variety

2. Electron Configurations and the Periodic Table W [Xe]4f145d46s2 W [Xe]4f146s25d4 Order can get mixed around in notation because of the preference to find the balance between showing the energy levels in order and showing which orbitals fill first. Variations can also be caused by individual preferences, arbitrary convention, or printing space availability.

2. Electron Configurations and the Periodic Table Orbital filling and the periodic table (Wave Mechanical Model) Periodic

2. Electron Configurations and the Periodic Table Group number tells the number of valence electrons!

3. Atomic Properties and the Periodic Table Metals and Nonmetals Metals tend to lose electrons to form positive ions. Nonmetals tend to gain electrons to form negative ions.

3. Atomic Properties and the Periodic Table Atomic Size Size tends to increase down a column. Size tends to decrease across a row. Biggest at lower left

3. Atomic Properties and the Periodic Table Ionization Energies Ionization Energy – energy required to remove an electron from an individual atom (gas) Tends to decrease down a column Tends to increase across a row Biggest upper right

3. Atomic Properties and the Periodic Table Ionization Energies Ionization Energy – energy required to remove an electron from an individual atom (gas) The key criticism of the Bohr model was that although it accurately predicted the ionization energies for hydrogen, it was lacking in its description of the ionization energies for the other atoms.

3. Atomic Properties and the Periodic Table Ionization Energies Ionization Energy – energy required to remove an electron from an individual atom (gas) Lithium Sodium and Potassium Rubidium and Cesium Francium Bomb

To learn about valence electrons and core electrons Objectives Review To understand how the principal energy levels fill with electrons in atoms beyond hydrogen To learn about valence electrons and core electrons To learn about the electron configurations of atoms with Z < 18 To understand the general trends in properties in the periodic table Work Session: Page 390 # 1-7