Metallic and Ionic Nanoparticles. Extendable Structures: Melting Point, Color, Conductivity. Iron Nanoparticles. How many grams of iron powder would it take to present a surface area equal to that of 1 gram of nanoparticles? ______.
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Melting Point, Color, Conductivity
High melting/boiling points
Changes in Physical Properties
take place at
What do these graphs tell us?
How many atoms make it macro?
5 nm diameter gold nanoparticles
The image represents nanoparticles in suspension.
All of them are the same size. Those that appear smaller are further away.
Adapted from F. G. Shi, J. Mater. Res., 1994, 9(5), 1307-1313,reproduced in Nanoscale Materials in Chemistry, edited by Kenneth J. Klabunde, 2001, John Wiley & Sons, Inc, New York, NY
Decreased melting points
Increased rates of some
Increased surface area to volume
ratios of nanoparticles
Bulk Gold Nano Gold
2-3 mm diameter
gold beads in toluene
4-5 nm diameter gold
nanoparticles in toluene
Courtesy of Kansas State University
All colors of light
are reflected from a smooth silver
Somebluelight is absorbedby a smooth gold surface
At the nano level
Color of lustrous
As particle size decreases, electromagnetic radiation interacts with free electrons to absorb, reflect, or transmit different colors of light.
Electrons in Atomic Orbitals
“sea of electrons”
s, p, d, and f atomic orbitals
electrons can be elevated
to higher energy levels
As particle size decreases, conductivity decreases
How and why do the chemical
and physical properties
of nanosamples differ
from those of macrosamples
of the same substance?
Lesson 1.1 What is Nanoscience?
What is Nanoscience?
Examine and Compare size: macro, micro, sub-micro (nano)
Lesson 1.2 What Makes Nanoscience so Different?
What makes Nanoscience so different?
Compare Newtonian and Quantum Chemistry Regimes as they relate to nanoscale science
Lesson 1.3 What Makes Nanoscience so Important?
The development of new technologies and instrumentation applications whose risk and benefits have yet to be determined
Students will further investigate the essential question that they have considered throughout the module: How and why do the chemical and physical properties of nanosamples differ from those of macrosamples?
Lesson 2.1Extendable Solids
As the size of the sample decreases the ratio of surface particles to interior particles increases in ionic and metallic solids
Lesson 2.2Extendable Solids: Reactivity, Catalysis, Adsorption
The difference between the energy at the surface atoms and energy of the interior atoms results in increased surface energy at the nanoscale
Higher surface energy allowing for increased reactivity, adsorption and catalysis at the nanoscale
Extendable Structures: Melting Point, Color Conductivity
In Extendable Structures:
Melting point decreases because surface energy increases
Color changes because electron orbital changes with decreased particle size
Electrical conductivity decreases because electron orbital changes with decreased particle size
Fullerenes and Nanotubes