8/23/2016 1 Unit 01 (Chp 6,7): Atoms and Periodic Properties Chemistry, The Central Science, 10th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten John D. Bookstaver St. Charles Community College St. Peters, MO 2006, Prentice Hall, Inc. Development of the Atomic Model • Indivisible • Identical • React in fixed ratios + • + stuff • – electrons • empty space • nucleus Na Li Cu Rutherford’s atomic model didn’t explain properties of matter (color, reactivity, …) Development of the Atomic Model
15
Embed
Unit 01 (Chp 6,7): Atoms and Periodic Properties · Unit 01 (Chp 6,7): Atoms and Periodic Properties Chemistry, The Central Science , 10th edition Theodore L. Brown; H. Eugene LeMay,
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
8/23/2016
1
Unit 01 (Chp 6,7):
Atoms and
Periodic Properties
Chemistry, The Central Science, 10th editionTheodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten
John D. BookstaverSt. Charles Community College
St. Peters, MO 2006, Prentice Hall, Inc.
Development of the Atomic Model
• Indivisible
• Identical
• React in fixed ratios
+• + stuff
• – electrons
• empty space
• nucleus
NaLi Cu
Rutherford’s atomic model didn’t explain
properties of matter (color, reactivity, …)
Development of the Atomic Model
8/23/2016
2
prism
helium
(He)lamp
prism
white light � continuous spectrum
elements � discrete lines of E & f
Atomic Emission Spectra
(only specific colors of energy & frequency)
A mystery for
Niels Bohr.
Hydrogen Emission Spectrum
e–’s emit
(–) energy, move back
to inner
levels(n=5 to n=2)
e–’s absorb
(+) energy, move to
outer
levels(n=2 to n=5)
EXCITED
state
GROUND
state
∆E
5
242
Which transition shows a light wave
of the greatest energy?
32
n=5 to n=2
(1913–Niels Bohr)Bohr’s Shell Model
+
8/23/2016
3
Photon Energy as Light Waves
• Distance between same point on adjacent
waves is the _______________. (m)
• Number of Waves passing a given point
per unit time is the ______________. (Hz)(s–1)
λλλλ and νννν are
_________ proportional
wavelength (λλλλ)
frequency (νννν)
inversely
All light waves
move at the same speed, so
which color has
more energy?
All EM waves travel the same speed:
the speed of light (c), 2.998 ×××× 108 m/s.c = λλλλνννν
R O Y G B I V
(higher E) (higher νννν) (shorter λλλλ)
Low Frequency High Frequency
Electromagnetic (EM) Spectrum
Low
Energy
High
Energy
8/23/2016
4
Photon (Light) Calculations
Given wavelength (λλλλ) of light, one can
calculate the energy (E) of 1 photon of that light:
E = hννννc = λλλλνννν (given on Exam)
HW p. 253
#14,25ab,26,34
λ , ν (inverse) E , ν (direct)
λλλλ↔ νννν νννν ↔ E
2.998 × 108 m/s 6.626 × 10–34 J•s(constants)
Schrödinger Wave Equation:
Heisenberg Uncertainty Principle: The more precisely a particle’s
motion is known,…
…the less precisely itsposition is known.(particle)
(wave)
3-D regions of probability (ORBITALS) in sublevelsin each fixed energy level which better explains reactivity.
(1926–Schrodinger, Plank, de Broglie, etc. )Quantum Mechanical Model
s , p , d , f
(E , λ , ν)
(probable locations)
“quantized” into specific multiples
ofwavelengths,
electrons occupy only specific levels (shells)of “quantized” energy
(& wavelength & frequency)
Electrons as Waves (instead of particles)
but none in between.
Quantum Mechanical Model
nucleus
8/23/2016
5
1803 Dalton
Atomic Theory
1904 Thomson
Plum Pudding
1911 Rutherford
Nuclear Model
1913 Bohr
Shell Model
1926 Quantum Mechanical
Model
Development of Atomic Models
+
+
–
–
––
–
–
1. (Shell) principle energy level (n) (1,2,3,4 …)
2. (Sub-shell) shape
3. (Orbital) 3-D arranged
4. (Electron) spin up/down
Where are the electrons really?
x z
s (1) p (3)(not rings)
d (5) f (7)
y
HW p. 255
#57ac, 60
1s2 2s2 2p4
energy
level(shell, n)
1s2 2s2 2p4
Orbital Notation
+8
Oxygen (O)
sublevel
shape(s,p,d,f)
1s2 2s2 2p4
Electron Configuration (arrangement)
# of e–’s in each sublevel
1s2 2s2 2p4
8/23/2016
6
Electron Configuration (arrangement)
1s2 2s2 2p41s2 2s2 2p4
+8
1s2 2s2 2p6 3s1Na
1s2 2s2 2p6 3s2 3p1
[Ne] 3s2 3p5 (noble gas core configuration)
Al
Cl
Oxygen (O)
How many valence e–’s?
6
(outer level)
E-Config? Element?
__
__
____________
1s2 2p3 3p6 4p23d10
(3d fills after 4s)
Aufbau: Fill lowest energyorbitals first.+
nucleus
Pauli Exclusion:no e–’s same props
(opp. spin) (↑↓)
Hund:1 e– in equal orbitals before pairing
(↑↑↑↓↓↓)
?
4s22p62s2 3s2
d orbital e–’s are core e–’s …NOT valence e–’s
Electron Configuration of IonsIon E-Con
(i) F–
(ii) Ca2+
(iii) S2–
(iv) Na+
(v) Al3+
1s2 2s2 2p6 [Ne]
1s2 2s2 2p6 3s2 3p6 [Ar]
1s2 2s2 2p6 3s2 3p6 [Ar]
1s2 2s2 2p6 [Ne]
1s2 2s2 2p6 [Ne]
Which ions are isoelectronic?F– , Na+ , Al3+ Ca2+ , S2–
List 3 species isoelectronic with Ca2+ & S2–.
P3– , Cl– , Ar, K+ , Sc3+ , Ti4+, V5+, Cr6+, Mn7+
8/23/2016
7
• Paramagnetic:
species attracted by a magnet
(caused by unpaired electrons).
Fe: [Ar] ↑↓ ↑↓ ↑ ↑ ↑ ↑4s 3d
• Diamagnetic:
species repelled by magnets
(caused by all paired electrons)
Zn: [Ar] ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓4s 3d
Other Aspects of Electron Configs
(“di-” is 2)
Other Aspects of Electron Configs
• d block metals lose their outer s electrons
before any core d electrons to form ions.
Fe 1s2 2s2 2p6 3s2 3p6 4s2 3d6
Fe2+ 1s2 2s2 2p6 3s2 3p6 3d6
Fe3+ 1s2 2s2 2p6 3s2 3p6 3d5
• d block (trans. metals) have colored ions
b/c light excites e– transitions in d orbitals
HW p.255
#74
Spectroscopy
SPECTROSCOPIC TECHNIQUE EM REGION APPLICATION
WATCH this 6 min Video Explanation of PES at HOME.
Microwave MicrowaveMolecular Structure by
molecular Rotation
IR Infrared Types of bonds by
bond Vibration
Vis/UV Atomic Emission Spectra
(lines of frequencies/colors)
Visible & Ultraviolet
Transition of e–’sbetween energy levels
PES (Photoelectron Spectroscopy) X-rayIonization of e–’sshows e– configuration