Post on 27-Dec-2015
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
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.
In what order will the orbits fill?
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 orbitalp = 3 orbitals
d = 5 orbitals f = 7 orbitalsorbital = 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.
This website shows different combinations of orbitals: http://www.orbitals.com/orb/orbtable.htm
Text Book Pg 131-2 shows orbital Pictures
Look at:s orbital: 1 shapep orbital: 3 same shape but different directionsd orbital: 5 orbitals
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. 7s….6s 6p 6d 6f 6g… 5s 5p 5d 5f 5g… 4s 4p 4d 4f 3s 3p 3d2s 2p 1s
(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 3d2s 2p 1s
(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 3d2s 2p 1s
(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 3d2s 2p 1s
(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 3d2s 2p 1s
(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 3d2s 2p 1s
(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 3d2s 2p 1s
(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
2. Pauli exclusions principle: an orbital may hold at most two electrons1s = 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 configurationsPut 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 configurationsH 1s1
He 1s2
Ne 1s2 2s2 2p6
Ar 1s2 2s2 2p6 3s2 3p6
Question: F9e- F 1s2 2s2 2p5
2p5 =second principle energy level, p-orbitals, with 5 electronsWhat 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. 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. When they drop, they produce
electromagnetic radiation.
See page 145 Bottom.Explained more in a few
slides.
electromagnetic radiation – all light waves. microwaves, visible light, infrared and
ultraviolet light…
Thermal imaging
Demo prism with OLD overhead projector light
or mirror and sunlightor Computer Projector on this slide made best rainbow.
Then have students look through diffraction gradient slides.
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 waveTrough: 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= 9.76 × 10-8 m)f = c/ λ
Calculate the frequency of a blue light emitted by a UV lamp.
(λ= 9.76 × 10-8 m)
f = 3.0 × 108 m/s / 9.76 × 10-8 m
f = 3.07 × 1015 Hz
f = c/ λ
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 theseelectrons lose energy by emitting light when they return to lower energylevels.
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 lightemitted by an electron moving from a higher to a lower energy
level has a frequencydirectly 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
HeisenbergUncertainty Principle
Pg 148
TheHeisenberg
uncertainty principlestates that it is impossible to know
exactly both thevelocity 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?!"