Ch 5 Electrons Use various atomic models to explain atomic behavior. Use the periodic table for atomic information.

Quiz on beyond question Mr. Burkholder, being the great guy that he is, will skip this quiz.

Rutherford’s atomic model did not explain complex properties of atoms

Bohr – e- could move to another energy level if it absorbed a quantum of energy

Pictures of the orbital shapes are on Page 131. The modern atom Schrödinger, shape is based on probability of finding the electron. Pictures of the orbital shapes are on Page 131.

Lower energy orbitals fill up first. Look at pg 135, textbook Lower energy orbitals fill up first. Look at pg 135, textbook. In what order will the orbits fill?

Energy order you need to memorize RED. (quiz Energy order you need to memorize RED! (quiz?) (Slide 15 shows how to memorize) (1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s,4d,5p) s = 1 orbital p = 3 orbitals d = 5 orbitals f = 7 orbitals orbital = region of 90% high probability of finding an e-

Also look at page 131 of text book.

Electron configurations: the way e- are arranged in orbit around the nucleus of an atom The period table was arranged before they knew about e-. P.T. is arranged by physical properties.

Text Book Pg 131-2 shows orbital Pictures Look at: s orbital: 1 shape p orbital: 3 same shape but different directions d orbital: 5 orbitals This website shows different combinations of orbitals: http://www.orbitals.com/orb/orbtable.htm

3 Rules for assigning electrons (w/o the exceptions)

1. Aufbau principle : electrons enter orbitals of lowest energy first Remember the quiz!!! (1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s,4d,5p)

Draw Orbitals of each principle energy level as a class. 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

(answers)Orbitals in each principle energy level (answers)Orbitals in each principle energy level. (Draw lines up and to the left to show lowest energy levels in order.) 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

(answers)Orbitals in each principle energy level (answers)Orbitals in each principle energy level. (Draw lines up and to the left to show lowest energy levels in order.) 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

(answers)Orbitals in each principle energy level (answers)Orbitals in each principle energy level. (Draw lines up and to the left to show lowest energy levels in order.) 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

(answers)Orbitals in each principle energy level (answers)Orbitals in each principle energy level. (Draw lines up and to the left to show lowest energy levels in order.) 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

(answers)Orbitals in each principle energy level (answers)Orbitals in each principle energy level. (Draw lines up and to the left to show lowest energy levels in order.) 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

(answers)Orbitals in each principle energy level (answers)Orbitals in each principle energy level. (Draw lines up and to the left to show lowest energy levels in order.) 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

(answers)Orbitals in each principle energy level (answers)Orbitals in each principle energy level. (Draw lines up and to the left to show lowest energy levels in order.) 6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d ETC. with 2s 2p the lines 1s Draw this in PP Notes

Pauli exclusions principle: an orbital may hold at most two electrons 1s = 2e- max(1 orbital) 2s = 2e- max 2p = 6e- max(2 x 3 orbitals) 3s = 2e- max 3p = 6e- max(2 x 3 orbitals) 4s = 2e- max 3d = 10e- max(2 x 5 orbitals)

Electron configurations Put a little number (looks like an exponent) to show number of electrons in the orbital. Start by listing all orbitals. Fill in numbers until you hit number of e-. 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 1e- H 1s1 2e- He 1s2 10e- Ne 1s2 2s2 2p6 18e- Ar 1s2 2s2 2p6 3s2 3p6

Electron configurations H. 1s1 He. 1s2 Ne. 1s2 2s2 2p6 Ar Electron configurations H 1s1 He 1s2 Ne 1s2 2s2 2p6 Ar 1s2 2s2 2p6 3s2 3p6 Question: F 9e- F 1s2 2s2 2p5 2p5 =second principle energy level, p-orbitals, with 5 electrons What element ends with 3d7 = ?

Remember: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 Electron configurations 1s2 2s2 2p6 3s2 3p6 4s2 3d7 = 27e- Co Review: 2p5 =second electron level, p shaped orbitals, with 5 electrons out of 6

Electron configurations: the way e- are arranged in orbit around the nucleus of an atom

3. Hund’s rule: when e- occupy orbitals of equal energy, one e- enters each orbital until all the orbitals contain 1e- then they pair up. Make all the singles you can before pairing.

3. Hund’s rule- when e- occupy orbitals of equal energy, one e- enters each orbital until all the orbitals contain 1e- then they pair up

3. Hund’s rule- when e- occupy orbitals of equal energy, one e- enters each orbital until all the orbitals contain 1e- then they pair up

3. Hund’s rule- when e- occupy orbitals of equal energy, one e- enters each orbital until all the orbitals contain 1e- then they pair up

3. Hund’s rule- when e- occupy orbitals of equal energy, one e- enters each orbital until all the orbitals contain 1e- then they pair up

3. Hund’s rule- when e- occupy orbitals of equal energy, one e- enters each orbital until all the orbitals contain 1e- then they pair up

3. Hund’s rule- Please look at page 135.

3 Rules for WOD: 1. Aufbau principle : Fill lowest energy orbital first. 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s,4d,5p 2. Pauli exclusions principle: 2 max e- per energy orbiral level. (Each orbital has 0, 1, 2 e-) 3. Hund’s rule: Make all the singles you can before making pairs.

Examples Do these in your Powerpoint notes. 1 Examples Do these in your Powerpoint notes. 1. How many unpaired electrons does sulfur have? 2. What is the e- configuration of B? 3. What is the e- configuration of Br? How many are unpaired?

Electron configurations 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 Sulfur has16e- 1s2 2s2 2p6 3s2 3p4 So unpaired is 2 because p is Boron has 5e- 1s2 2s2 2p1 Bromine has 35e- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 1 unpaired

Electromagnetic Radiation                                                                              

Electromagnetic Radiation: Electrons can change levels Electromagnetic Radiation: Electrons can change levels. When they drop, they produce electromagnetic radiation. See page 145 Bottom. Explained more in a few slides.                                                                              

electromagnetic radiation – all light waves electromagnetic radiation – all light waves. microwaves, visible light, infrared and ultraviolet light…                                                                              

Thermal imaging

Demo prism with OLD overhead projector light or mirror and sunlight or Computer Projector on this slide made best rainbow. Then have students look through diffraction gradient slides.

Wave

Wavelength, λ: distance between crests Frequency, f: number of wave cycles to pass a given point per unit of time(waves per second.) Hertz, Hz: Waves per Second (frequency) Amplitude: height of wave above zero or the middle. Crest: Top of wave Trough: Bottom of wave

to calculate frequency, c= speed of light 3.0x10 8 m/s f = c λ Frequency is speed of light divided by the wavelength

Calculate the frequency of a blue light emitted by a UV lamp. (λ= 9 Calculate the frequency of a blue light emitted by a UV lamp. (λ= 9.76 × 10-8 m) f = c/ λ

Calculate the frequency of a blue light emitted by a UV lamp. (λ= 9 Calculate the frequency of a blue light emitted by a UV lamp. (λ= 9.76 × 10-8 m) f = c/ λ f = 3.0 × 108 m/s / 9.76 × 10-8 m f = 3.07 × 1015 Hz

Show EM Brain Pop. Stop it 1min and have students copy EM spectrum Show EM Brain Pop. Stop it 1min and have students copy EM spectrum. Stop again at Visible Light 2:10? and have students copy ROYGBIV.

Atomic Emission Spectrum:

Atomic emission spectrum: passing the light emitted by an element through a prism Each line is a specific energy of light. Each is unique to that element

Atomic Emission Spectrum: The different colors each element produces when excited as seen through a prism.

Each discrete line corresponds to one exact frequency of light emitted by the atom.

Rainbow brainpop shows how prisms work.

When atoms absorb energy, electrons move into higher energy levels, and these electrons lose energy by emitting light when they return to lower energy levels.

The lowest possible energy of the electron is = ground state = electrons absorb a quantum of energy and move into a higher excited state = they release this energy as electromagnetic radiation when they move back to the ground state Pg 145 of textbook

The light emitted by an electron moving from a higher to a lower energy level has a frequency directly proportional to the energy change of the electron. i.e., the distance between levels jumped determines the color (and energy) of light.

energy emitted by an electron is proportional to energy change of the electron E=h×υ   h = Planck’s constant 6.6262 × 10 -34 J·s

Heisenberg Uncertainty Principle Pg 148

The Heisenberg uncertainty principle states that it is impossible to know exactly both the velocity and the position of a particle at the same time. Shine a photon generator on a student and ask if they move (a flashlight). Then explain why an electron would move.

In a nutshell it states that it is impossible to know both the exact velocity and position of an electron at any point in time within certain margins of error. This is because the act of observation itself disturbs the system. "Would the tree have fallen over in the forest if we had not seen it?!"