Structure of the Atom Edward A. Mottel Department of Chemistry Rose-Hulman Institute of Technology
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Structure of the AtomEdward A. Mottel
Department of Chemistry
Rose-Hulman Institute of Technology
04/18/23
Heated cathodesemitted cathode "rays"
+
-
Deflected by eithermagnetic or electric fields
Cathode Ray Tube
J.J. Thomson, 1897
Turn thefield on & offby clicking on the + & -
04/18/23
The "beam" carrieda negative charge. +
-
J. J. THOMSON (1897)British Physicist
The ratio of chargeto mass (e/m) was
independent ofthe cathode material.
Why does this indicate thatcathode rays (electrons)
are an integral part of each element?
How did heknow that?
04/18/23
Blackbody Radiation
According to classical theory,the intensity of black body radiation should
be related to wavelength.
1300 K
1800 K
2000 K
1000 3000 5000
Wavelength (nm)
Inte
nsi
ty In fact,
the intensity peakedand then dropped off.
04/18/23
Blackbody Radiation
1300 K
1800 K
2000 K
1000 3000 5000
Wavelength (nm)
Inte
nsi
ty This failure of theory in
the ultraviolet regionof the spectrum,
was called the
"UltravioletCatastrophe”.
It impliedthat theenergies inan atom are limited or quantized.
Based on this, Max Planck (1901, German Physicist) developed a quantum theory that electrons in an atom
can have only specific energies.
04/18/23
Photoelectric Effect
+ -
Albert Einstein (1905)German Physicist
Interpreted thePhotoelectric Effect
Confirmed thatlight is corpuscular(possess particle-like properties)Blue Red
Light SourceLight SourceLight Source
04/18/23
Oil Drop Experiment
+
-
Robert Millikin (1909)American Physicist
Determined theabsolute chargeof an electron(4.8 x 10–10 esu)
04/18/23
Gold Foil Experiment(10-4 cm thick)
Kotz & Purcell (1987)
Rutherford, 1911
04/18/23
Ernest Rutherford (1911)British Chemist
Most of the alpha particles(a, 4He2+) passed straightthrough, buta few weredeflected orreflectedstraightbackwards.
Since alpha particleswere known to have
a positive charge,this indicated thatthe nucleus of an
atom containedmost of the mass,
and that it waspositive in charge
Diagram source unknown
04/18/23
Niels Bohr (1913)(Danish Physicist)
Postulated that electrons spin around the nucleus in an orbit.
The energy differencesbetween these orbitscan be used to explainthe various colors of lightemitted and absorbedby gaseous elements.
04/18/23
Henry Moseley (1914)(British Physicist)
Developed a periodic table based on increasing atomic number.• Each element has an unique "spectra"
(wavelengths or colors of light) that they emit when heated to glowing.
04/18/23
Emission Spectra
• The spectra contains many colors (wavelengths) which are not uniformly spaced.
K bandL bandM band
Energy
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Development of the Periodic Table
Element MassAtomic Number
K Inverse Sqrt(K)
Li 6.94 3 226.6 0.066Be 9.01 4 110.7 0.095B 10.81 5 66.3 0.123C 12.00 6 43.6 0.151N 14.01 7 31.0 0.180O 16.00 8 23.3 0.207
(Å)
04/18/23
K Radiation of Light Weight ElementsR2 = 0.9951
0.00
0.05
0.10
0.15
0.20
0.25
5 10 15 20
Mass (amu)
1/sq
rt(K
)
04/18/23
Integer Relationship of K RadiationR2 = 1
0.00
0.05
0.10
0.15
0.20
0.25
2 4 6 8 10
Integers
1/sq
rt(K
)
Atomic Number
04/18/23
Erwin Schrodinger (1926)(Austrian Physicist)
Developed the modern view of the atom, treating electrons as mathematical functions.• sine and cosine wave functions.
Louis de Broglie (1926)(French Physicist)
Proposed that matter has both wave and particle properties.
04/18/23
James Chadwick (1932)(British Physicist)
Determined the existence of the uncharged neutron.• Neutrons reside along with protons in the
nucleus and explain the fact that elements have isotopes.
04/18/23
Protons, Neutrons and Electrons
Fluorine atom
F199
charge(protons & electrons)
mass numberprotons & neutrons atomic number
(protons)
How many protons, neutrons and electronsare in a fluorine atom?
04/18/23
Protons, Neutrons and Electrons
Chloride ion
Cl–3717
charge(protons & electrons)
mass numberprotons & neutrons atomic number
(protons)
How many protons, neutrons and electronsare in a chloride ion?
04/18/23
Protons, Neutrons and Electrons
Aluminum ion
Al3+2713
How many protons, neutrons and electronsare in an aluminum ion?
04/18/23
Using the Periodic Table
Monatomic ions (ions containing only one atom) often have a charge that can be derived directly from the periodic table.
04/18/23
+1 ionsHLi Be
MgNa
K Ca
Rb Sr
CsBa
Ti CrMn Fe Co Ni CuZn
Pd
Pt
Ag
Au
Cd
Hg Tl
SnPb Bi
Sb
AsI
Br
Cl
O FSAl
04/18/23
+2 ions
Au
Ag
HLi Be
MgNa
K Ca
Rb Sr
CsBa
Ti CrMn Fe Co Ni CuZn
Pd
Pt
Cd
Hg Tl
SnPb Bi
Sb
AsI
Br
Cl
O FSAl
04/18/23
+3 ionsHLi Be
MgNa
K Ca
Rb Sr
CsBa
Ti CrMn Fe Co Ni CuZn
Pd
Pt
Ag
Au
Cd
Hg Tl
SnPb Bi
Sb
AsI
Br
Cl
O FSAl
04/18/23
-1 ionsHLi Be
MgNa
K Ca
Rb Sr
CsBa
Ti CrMn Fe Co Ni CuZn
Pd
Pt
Ag
Au
Cd
Hg Tl
SnPb Bi
Sb
AsI
Br
Cl
O FSAl
04/18/23
Coordination Compound NomenclatureEdward A. Mottel
Department of Chemistry
Rose-Hulman Institute of Technology
04/18/23
Coordination Compounds
Metal ion• the central atom
Ligand• atom, ion or molecule bound to the metal
The nomenclature of a salt anda coordination compound
are different.
04/18/23
Salt Nomenclature
FeCl3Fe3+ ion
iron(III) chloride
Salt (ionic) nomenclature only indicatesthe stoichiometry of the compound.
requires 3 Cl–
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Coordination Compound Nomenclature
FeClClCl
Cl
Cl
Cl
3-hexachloroferrate(III) ion
Coordination compound nomenclaturecommunicates the environment of the central ion.
the iron ion is coordinatedto six chloride ligands
04/18/23
Coordination Compound Nomenclature
Fe
3+
OH
HOH
H
OH
H OH
HOH H
OH H
Coordination compound nomenclaturecommunicates the environment of the central ion.
hexaaquairon(III) ion
the iron ion is coordinatedto six water ligands
04/18/23
Nomenclature of Inorganic Coordination Compounds
Cation/anion sequence Ligand names Cationic/anionic complexes Alphabetical sequencing Brackets
04/18/23
[Cu(NH3)2Cl2]
[Cu(NH3)4]2+
[CuCl4]2–
Name each of the following
diamminedichlorocopper(II)
tetramminecopper(II) ion
tetrachlorocuprate(II) ion
04/18/23
Nomenclature of Inorganic Coordination Compounds
What is the meaning of Roman numerals in parenthesis?
When is copper used and when is cuprate used?
Meaning of the words aqua, ammine, cyano, chloro, bromo, iodo?
Application of the prefixes di, tri, tetra, … Order in which the words are used?
04/18/23
04/18/23
04/18/23
Heated cathodesemitted cathode "rays"
+
-
Deflected by eithermagnetic or electric fields
Cathode Ray Tube
J.J. Thomson, 1897
04/18/23
Photoelectric Effect
+ -
Albert Einstein (1905)German Physicist
Interpreted thePhotoelectric Effect
Confirmed thatlight is corpuscular(possess particle-like properties)
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