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Waves. Crest Trough Amplitude – half the height Wavelength – distance from one point on one wave to the same point on an adjacent wave Frequency – Number of times a wave passes a point in one second (Hertz). Waves. Frequency & Wavelength – Frequency & Energy – Wavelength & Energy – - PowerPoint PPT Presentation
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Electrons In Atoms
1. Crest2. Trough3. Amplitude – half the height4. Wavelength – distance from one point on
one wave to the same point on an adjacent wave
5. Frequency – Number of times a wave passes a point in one second (Hertz)
Waves
Electrons In Atoms
• Frequency & Wavelength –
• Frequency & Energy –
• Wavelength & Energy –
• Amplitude & Energy -
Waves
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
•How many complete waves are shown above?•What is the wavelength of light shown above?
Electrons In Atoms
Blu-Ray = 405 nanometers (blue light)
DVD = 650 nanometers (red light)
a. Calculate the number of wavelengths for each wave shown to the left.
b. Calculate the wavelength of each wave.
c. 1 nm = 1 X 10-9 m. Convert each wavelength to nm.
d. Which of the waves would be in the visible range?
Electrons In Atoms
1. All electromagnetic radiation moves at speed of light (186,000 mi/s or 3 X 108 m/s)
2. All EM radiation is a form of light
3. Visible light = 400 nm to 700 nm
violet red
Light
Light
Radio Radar Micro IR Visible Light
UV X-rays
Gamma
The Electromagnetic Spectrum
Safe radiation (non-ionizing) Dangerous (ionizing)
Produced by nuclear decay
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
MicrowavesTraditional Heat – increase translational motion of waterMicrowaves – increase rotational motion of water
Electrons In Atoms
Traditional Heat Microwaves
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Electrons In AtomsLight
Electrons In Atoms
Electrons In Atoms
c =
c = speed of light (3 X 108 m/s)
= wavelength (meters) = frequency (Hz or s-1)
Important conversion 1 nm = 1 X 10-9 m
Electrons In Atoms
Calculate the wavelength of a 60 Hz EM wave
5 X 106 m
Electrons In Atoms
Calculate the wavelength of a 98.5 MHz FM radio station
3.05 m
Electrons In Atoms
Calculate the frequency of 500 nm blue light.
6 X 1014 s-1
Electrons In Atoms
6. Wave-Particle Duality
a. light can be viewed as both a wave and a particle
b. Max Planck/Einstein ~1910
c. Photon – has no mass, only energy
Light
Electrons In AtomsLight
Electrons In Atoms
E = h(for one photon)
E = Energy (J)
h = 6.63 X 10-34 J s (Planck’s constant)
= frequency (Hz)
Electrons In Atoms
Calculate the energy of laser light with a frequency of 4.69 X 1014 s-1 .
Ans: 3.11 X 10-19 J (This is for one photon)
Electrons In Atoms
Calculate the energy of a photon of wavelength 600 nm.
ANS:3.3 X 10-19 J
Calculate the energy of a photon of wavelength 450 nm (blue light).
Ans: 4.42 X 10-19 J (This is for one photon)
A single photon has an energy of 3.616 X 10-19 J.
a. Calculate the frequency of the photon.
b.Calculate the wavelength of a photon in meters
c. Calculate the wavelength of a photon in nanometers.
d.Is this photon in the visible range?
e. What range of the spectrum would you expect a photon of 800 nm to be?
f. Calculate the energy for one mole of photons with individual energies of 3.616 X 10-19 J.
a. 5.45 X 1014 Hz
b. 5.50 X 10-7 m
c. 550 nm
d. Yes
e. IR
f. 3.616 X 10-19 J X 6.02 X 1023 photons
1 photon 1 mole
=2.18 X 105 J/mol
Electrons In Atoms
My = 8.1 X 10-36 m at 3 mph
Newtonian Mechanics Quantum Mechanics
Everything is a particle Everything is both a wave and a particle
Large objects (dust, people, baseballs, etc..)
Photons, electrons, atoms, molecules
All values are allowed Quantized – only certain values allowed
Predictable Probabilistic
Electrons In Atoms
1. Neils Bohr Planetary Model
2. Studying line spectra of elements
– Only certain lines are present (quantized)
– Not a rainbow– Spectra are a fingerprint for
atoms/molecules (Astronomy)
Bohr Model
Electrons In Atoms
Electrons In Atoms
Quantized – only certain orbits exist (rest is forbidden zone)
4. Ways to make something glow
Bohr Model
Photon Absorption Collision-Glow in the dark -Heat
-Electricity-Chemical Reaction
Photon Absorption Collision
Electrons In Atoms
Electrons In Atoms
A single photon has a wavelength of 150 nm.a.Calculate the wavelength of a photon in meters (1.50 X 10-7 m)b.Calculate the frequency of the photon. (2.0 X 1015 Hz)c.Calculate the energy of the photon. (1.33 X 10-18 J)d.Is this photon in the visible range?e.Calculate the energy for one mole of these photons. (8.01 X 105 J)
Electrons In Atoms
Electron as a particle
Heisenberg Uncertainty Principle – can never know both the position and velocity of an electron at the same time
Quantum Mechanical Model
Electrons In Atoms
a. Electron cloud b. Electron moves randomly (not like a planet)c. Orbital – region of 90% probability
Electrons In Atoms
nucleus
Random electron
cloud
Electrons In Atoms
Electron as Wave
Schrodinger Wave Equation (1926) – treats electron solely as a wave
Quantum Mechanical Model
Electrons In Atoms
Electrons In Atoms
Result One - Explains the forbidden zone (waves do not match)
Quantum Mechanical Model
Electrons In Atoms
Quantum Mechanical Model
Waves match here (get a clear note)
Waves do not match here
(get a bad note, forbidden zone)
Electrons In Atoms
Result Two
Orbits are not circular
Quantum Mechanical Model
Electrons In AtomsBohr Model Heisenberg
(Particle)
Schrodinger
(Wave)
Explains line spectra
Planetary model
Electron moves randomly
Electron cloud
Explains f. zone
Shapes of orbits
1. Draw an s, p and d orbital
2. How many electrons can be placed in an s orbital?
3. How many electrons can be placed in an p orbital? In a p suborbital?
4. How many electrons can be placed in an d orbital? In a d suborbital?
5. How many electrons can be placed in an f orbital? In an f suborbital?
6. How did Heisenberg consider the electron?
7. How did Schrodinger consider electron?
Electrons In Atoms
First QN – how far the electron is from the nucleus (larger the number, farther away) – Level or shell
Quantum Numbers
n = 2
n = 1
Electrons In Atoms
Second QN – the shape of the orbital
Quantum Numbers
Electrons In Atoms
Third QN – the suborbital
Orbital # suborbitals Total e-
s 0 2
p 3 (px,py,pz) 6d 5 10f 7 14
Quantum Numbers
Electrons In Atoms
Electrons In Atoms
Electrons In AtomsQuantum Mechanical Model
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Fourth QN – spin of the electron
Pauli Exclusion Principle – two electrons in the same suborbital (ex: px) must have opposite spins
+1/2 -1/2
Quantum Numbers
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Electrons In Atoms
Electron Configuration
Electrons In Atoms
1. Electron Configuration – shorthand notation to tell you the locations of all the electrons in an atom or ion
2. Notation
2p3
Orbit Shape # e-
Electron Configurations
Electrons In AtomsElectron Configurations
Electrons In Atoms
Electrons In Atoms
H
He
Li
O
Fe
S
Electron Configurations
Be V
N F
Sr Ar
P Mg
Se Kr
Which element is represented by the following electron configurations?
1s22s22p63s23p64s23d5
1s22s22p63s23p64s23d104p65s24d7
1s22s22p63s23p64s1
1s22s22p63s23p3
1s22s22p63s1
1s22s22p63s23p2
1s22s22p63s23p64s23d104p6
Electrons In Atoms
1. Rule – Use the noble gas in the previous row2. Examples
NePRuKr
You try:
Br Ar S Ca I Xe
Noble Gas Shortcut
Br I
Ar Ca
S Xe
Electrons In AtomsExceptions
• Mostly with transition metal elements
• There is a special stability to filled and half-filled orbitals
Element Actual configuration Instead of
Cr [Ar]4s13d5 [Ar]4s23d4
Mo [Kr]5s14d5 [Kr]5s24d4
Cu [ Ar]4s13d10 [Ar]4s23d9
Ag [Kr]5s14d10 [Kr]5s24d9
Electrons In Atoms
p e e- configuration
Sr
Sr+
Sr2+
Ions
Electrons In Atoms
p e e- configuration
SS1-
S2-
Br1-
Ba2+
Ions
p e E configuration
Na+
P3+
P3-
Sn2+
B3+
Se2-
Cl-
As3-
F1-
Ca2+
N2+
S2-
As3-
Electrons In Atoms
1. Outershell Electrons
2. Only Electrons involved in bonding
3. H2O example
4. Many elements want 8 valence electrons (Noble Gas Configuration)- Full Octet
Valence Electrons
Electrons In Atoms
Electrons In Atoms
e config #ve Lewis dot
HLiBeMg
Valence Electrons
Electrons In Atoms
e config #veLdot
OSCGe
Valence Electrons
Electrons In Atoms
e config Ldot
NaNa+
MgMg+
Mg+2
Valence Electrons
Electrons In Atomse config Ldot
B
B1+
B2+
B3+
Te
Te1-
Te2-
Valence Electrons
Electrons In Atoms
e config Ldot
Be
Be+
Be2+
Valence Electrons
Electrons In Atoms
e config #ve Ldot
ClCl-
OO1-
O2-
Valence Electrons
Electrons In Atoms
Gr I Gr II Gr III Gr IV Gr V Gr VI Gr VII
Gr VIII
1
v. e-
2
v. e-
3
v. e-
4
v. e-
5
v. e-
6
v. e-
7
v. e-
8
v. e-
+1 +2 +3 No charg
e
-3 -2 -1 0
Electrons In AtomsPeriodic Properties
Periodic Properties – Properties that depend on an element’s position on the table
Ex: Groups
H, Li, & Na all form similar oxides
(H2O, Li2O, Na2O)
Location gives you A LOT of information
Electrons In Atoms
Electrons In AtomsSize of Atoms
Atomic Radius
1. Measured in
picometers (1pm = 1 X 10-12 m) or Angstroms (1 Å = 100 pm)
2. Average radius ~100 pm (1 Å)
Electrons In Atoms
Electrons In AtomsSize of Atoms
3. Example: Bromine 1.14 Å
1.14 Å X 100 pm = 114 pm
1 Å
Electrons In Atoms
Effective Nuclear Charge
Charge from nucleus that
is not blocked (shielded)
by core electrons
Zeff = Z-S
Z = # protons
S = # core electron
Electrons In Atoms
What is the Zeff for Lithium (1s22s1)?
Electrons In Atoms
What is the Zeff for Fluorine ([He]2s22p5)?
e- configuration Zeff
S
O
P
O2-
Mg2+
K+
Electrons In AtomsSize of Atoms
Down a group
e- config Levels Zeff
H
Li
Na
Electrons In AtomsSize of Atoms
Down a group – atoms get larger, more levels
e- config Levels Zeff
H
Li
Na
Electrons In AtomsSize of Atoms
Electrons In AtomsSize of Atoms
Across a period – atoms get smaller. Same levels, greater Zeff (nucleus pulls electrons closer)
Li F
E config
levels
Zeff
Electrons In AtomsSize of Atoms
Electrons In AtomsSize of Atoms
Si Cl
E config
levels
Zeff
Electrons In AtomsSize of Ions
A. Positive Ions
1. Example:
Mg Mg+ Mg2+
E config
levels
Zeff
electrons
Electrons In AtomsSize of Ions
Electrons In AtomsSize of Ions
Positive ions always smaller– Fewer electrons to control– Less e- to e- repulsion
Electrons In Atoms
Mg Mg+ Mg2+
E config
levels
Zeff
electrons
Electrons In AtomsSize of Ions
B. Negative Ions
1. Example:
O O2-
E config
levels
Zeff
electrons
Electrons In AtomsSize of Ions
Electrons In AtomsSize of Ions
Negative ions always larger– More electrons to control– More e- to e- repulsion
a. Rank the three elements from smallest to largest
b.Which factor is most important in comparing Mg and Sr, levels or Zeff? Explain.
c. Which factor is most important in comparing Mg and S, levels or Zeff? Explain.
d.Which would be larger, S or S2-? Explain.
Mg S SrElectron Config.
Levels
Zeff
Electrons In AtomsMore levels
Greater Zeff
(same levels, greater Zeff smaller)
IonsPositive = Smaller(less electron repulsion)
Negative = Larger (more electron repulsion)
If same
If same
Size ReviewWhich is larger and why?Li or K
S or S2+
Mg or S
O or Te
Size ReviewWhich is larger and why?Cl or Al
B or B+
Al or In
B or B-
Electrons In AtomsSize Review
KurveballK or K+
Electrons In AtomsIonization Energy
A.Ionization energy – The energy needed to remove an electron from an atom
Na Na+ + e-
Electrons In Atoms
A low energy photon will excite an electron
A high energy photon may ionize an atom (completely remove the electron)
He
Ne
Ar
KLi Na
H
Electrons In AtomsIonization Energy
B. Across a period – Ionization Energy INCREASES
1. Harder to remove an electron (atom is smaller, holds e- more tightly)
2. Examples:
Li (520 kJ/mol) F (1681)
Electrons In Atoms
Electrons In AtomsIonization Energy
C. Down a group–Ionization Energy DECREASES1. Easier to remove an electron (atom is larger, holds e- more loosely)2. Examples:
Li (520 kJ/mol)
Na (496 kJ/mol)
K (419 kJ/mol)
Electrons In AtomsIonization Energy
Which has the higher Ionization Energy and why?
C or O
Na or Cl
C or Sn
Mg or Ra
Multiple Ionization Energy
Multiple Ionizations - Removing more than one electron1st Mg Mg+ + e- 738 kJ/mol2nd Mg+ Mg2+ + e- 1450 kJ/mol3rd Mg2+ Mg3+ + e- 7732 kJ/mol
There is a large jump once you reach Noble Gas
Configuration (Fewer levels, spike in Zeff)
Multiple Ionization Energy
Multiple Ionization Energy
1st Al Al + + e- 577 kJ/mol
2nd Al + Al 2+ + e- 1816 kJ/mol
3rd Al 2+ Al 3+ + e- 2744 kJ/mol
4th Al3+ Al4+ + e- 11580 kJ/mol
Multiple Ionization Energy
Examples:
a. Where will the large jump in I.E. occur for:
Be B P
b. Element X has a large jump between its 4th and 5th I.E. To what group does it
belong?
Size ReviewWhich is larger and why?N or N3-
C or F
Sr or Be
O or O2-
Size ReviewWhich has the larger ionization
energy and why?P or P3+
B or F
Ba or Be
S or Na
Electrons In Atoms
1. Spectroscopy
2. Spec 20
a. Light Source
b. Slit
c. Prism/Monochromator
d. Sample
e. Light Meter (PMT)
Light
Emission Spectrum of Air
Wavelength(nm) Wavelength(m) Frequency (Hz) Energy (J)
550 5.50 X 10-7 5.45 X 1014 3.61 X 10-19
120 1.20 X 10-7 2.50 X 1015 1.66 X 10-18
0.115 1.15 X 10-10 2.61 X 1018 1.73 X 10-15
1490 1.49 X 10-6 2.01 X 1014 1.33 X 10-19
405 4.05 X 10-7 7.41 X 1014 4.91 X 10-19
650 6.50 X 10-7 4.62 X 1014 3.06 X 10-19
800 8.00 X 10-7 3.75 X 1014 2.49 X 10-19
14.9 1.49 X 10-8 2.01 X 1016 1.33 X 10-17
2a. 1 X 10-7 m
b.3 X 1015 Hz
c. 1.99 X 10-18 J
d.400-700 nm
e. UV
3a. 6 X 10-7 m
b. 600 nm
c. 3.31 X 10-19 J
d.Red
e. Longer
Page 231 “Assessing”
8-2 a
Orbital
s, p, d, f
spherical
p-orbital
3 subshells
p orbitals
8-3 a) 18 b) 3 c) 2, 6, 10 d) 0,3,5
8-1 UV light has higher energy (shorter wavelength)
8-2 n=9 to n=1 will have a shorter wavelength
8-3 n=3 to n=1 will have a shorter wavelength
8-4 Excited state, Li is only in the second period
8-5 1p and 3f
8-6 2d does not exist
Li 1s22s1
Br 1s22s22p63s2 3p64s23d104p5
In 1s22s22p63s2 3p64s23d104p65s2 4d105p1
Ne 1s22s22p6
N 1s22s22p3
Ca 1s22s22p63s2 3p64s2
Al 1s22s22p63s2 3p1
S 1s22s22p63s2 3p4
Kr 1s22s22p63s2 3p64s23d104p6
Zr 1s22s22p63s2 3p64s23d104p65s2 4d2
Fe 1s22s22p63s2 3p64s23d6
C 1s22s22p2
Ar 1s22s22p63s2 3p6
Pd 1s22s22p63s2 3p64s23d104p65s2 4d8
He 1s2
O 1s22s22p4
Ti 1s22s22p63s2 3p64s23d2
Na 1s22s22p63s1
Mg 1s22s22p63s2
Si 1s22s22p63s2 3p2
C 1s22s22p2
Ne [He]2s22p6 S [Ne]3s23p4
Si [Ne]3s23p2 In [Kr]5s24d105p1
Sr [Kr]5s2 K [Ar]4s1
Fe [Ar]4s23d6 Cu [Ar]4s23d9
Te [Kr]5s24d105p4
P [Ne]3s23p3
N [He]2s22p3
Ni [Ar]4s23d8
Br [Ar]4s23d104p5
Be [He]2s2
[Ne]3s2 Mg
[Ar]4s23d3 V
[Kr]5s24d105p5 I
[Ar]4s23d104p6 Kr
[He]2s22p6 Ne
[Ne]3s23p5 Cl
O [He]2s22p4 Al [Ne]3s23p1
O1- [He]2s22p5 Al+ [Ne]3s2
O2- [He]2s22p6 Al2+ [Ne]3s1
Mg [Ne]3s2 Al3+ [He]2s22p6
Mg1+ [Ne]3s1 Cl [Ne]3s23p5
Mg2+ [He]2s22p6 Cl1- [Ne]3s23p6
N [He]2s22p3 Cl3+ [Ne]3s23p2
N3- [He]2s22p6
N3+ [He]2s2
N5+ 1s2
Electrons In Atoms4. Excited state, can emit a photon
6. 2d does not exist (d’s start with 3d)
7. Area of space where an electron is likely to be found
10.4 lobes (eggs), 4p has only 2 eggs
68. a) Tl b) Y c) Ce d) As
70. 141 pm = Sn 180 pm = Tl
Electrons In Atoms1. Ba(NO3)2
2. N2O4
3. Fe2(SO4)3
4. copper(II) chloride
5. nitrogren trihydride
6. Aluminum hydroxide
Electrons In Atoms2 1,13 1,2 2,14 1,3 3,1 2,25 1,4 4,1 2,3 3,26 1,5 5,1 2,4 4,2 3,37 1,6 6,1 2,5 5,2 4,3 3,48 2,6 6,2 3,5 5,3 4,49 3,6 6,3 4,5 5,4104,6 6,4 5,511 5,6 6,5126,6
67 a) As b) Ru c) Ba d) I
68 a) Tlb) Y c) Ce d) As
69 Cr = 117 pm, Nb = 134 pm
70 Sn = 141 pm, Tl = 180
71 a) V b) Cl c) Mg d) Fe e) B
Ca – More levels
Br- - Same levels and Zeff, more e- to control
Mg - Same levels, lower Zeff
Sb - More levels
Li – More levels
Sn – More levels
F – Smaller atom (same levels, higher Zeff)
C – Smaller atom (fewer levels)
Mg+ - Smaller atom (same levels, fewer electrons)
S - Smaller atom (same levels, higher Zeff)
Al3+ – Smaller atom (fewer levels)
Sr More levels
Sr Same levels, Sr has a lower Zeff
Sn Same levels, same Zeff, Sn has more e to e
repulsion
Te2- Same levels, same Zeff, Te2- has more e to e
repulsion
Fr More levels
Al2+ More levels
K Smaller atom, holds electrons more tightly
Cl Smaller atom, holds electrons more tightly
Ba2+ Smaller atom, holds electrons more tightly
Al Between 3rd and 4th
Rb Between 1st and 2nd
Ra Between 2nd and 3rd
Answers to Review Test1 C 11 D
2 B 12 B
3 A 13 A
4 B 14 C
5 A 15 D
6 D 16 E
7 B 17 D
8 A 18 C
9 C 19 B
10 B 20 D
E config L. Dot
S
S1-
S2-
Na+
Mg2+