Transcript Democritus (ca. 460 –ca. 370 BC)

•“Color exists by convention,
•sweet by convention,
•bitter by convention;
•in reality nothing exists but atoms and
the void.”
•Democritus (ca. 460 –ca. 370 B.C.)
Understanding Size
1st cut
2nd cut
• 1st cut
pocket
14cm
• 2nd cut
7cm
• 3rd cut
3.5cm
• 4th cut
1.75cm
keyboard key
jean
finger
eye
• 6th cut
.44cm
poppy seed
• 8th cut
1mm
Thread
• 12th Cut
.06mm
Human hair
• 18th cut
1micron
bacteria
• 19th cut
.5micron
• 24th cut
.015micron cell membrane
• 31st cut
.0001micron
light wave
atom!!!
• http://micro.magnet.fsu.edu/primer/java/sci
enceopticsu/powersof10/
http://www.purchon.com/chemistry/atoms.htm
The Big Picture
Periodic Table Organization
• Extremely organized by…..
– Atomic mass
• Protons + Neutrons = atomic mass
– Atomic number
• Atomic number = number of protons = number of
electrons
• NOTE: the number of protons MUST equal the
number of electrons in a stable atom (WHY?)
Electrons will enter the third
energy level only after the
second is full. The third
energy level can hold up to
18 electrons.
Valence Electrons: Electrons in the outer most shell of an atom.
These electrons are involved in chemical bonding
How & why atoms combine
or
Why the universe is run by
a teenager
Rule #1:
Quantity = Quality
• # Protons determines type of atom, usually
determines # of electrons.
Rule #2:
Atoms have stereotypes
Each Row
has the
same
number of
energy
levels
Rule#3
Atoms form cliques
Each
column or
family has
the same
number of
electrons
in the
outer level
Rule #4
Atoms want to be independent
Rule #5
If you can’t do it…Fake it
Lots of
energy
stored
Less
energy
stored
• http://visservices.sdsc.edu/projects/discov
ery/
Rule# 6
Always take the easy way
or
it’s better to have your own
then to share
Lucky for
us!
Bonding
The Specifics