1
Overview
•
Ch. 2: Basic Chemistry
– Chemical elements
– Compounds & molecules
– Water
– Acids & bases
Chemical Elements
• Elements
– Substance that cannot be broken down into simpler substances
• Atoms
– Smallest part of an element with properties of that element
Elements in Cells
•
96% : H, C, N, O
•
Remaining 4%: Ca, P, K, S, Na, Cl, Mg, Fe, I, Cu, Mn, Co, Zn, + trace
Atoms
• Atom
– Proton (
p
+
)
– Neutron (
n
0
)
– Electron (
e
-
) in electron shell
•
Mass number
– # protons + # neutrons
•
Atomic number
– # protons
Example: Carbon
Periodic Table
•
Appendix D of text
– Partial: Figure 2.3
•
Atomic mass
– Average AMU for all isotopes
•
Atoms in same group
– Similar binding characteristics
– Group VIII: noble gases
Isotopes
•
Differ in # neutrons
•
Radioactive isotopes*
•
Low levels of radiation
– Tracers
– Image body’s organs and tissues
•
High levels of radiation
– Irradiation to kill pathogens
– Radiation therapy to kill cancer cells
Electrons & Energy
• Electrons
– Not possible to determine exact location
•
Electron shells = energy levels
– The Bohr model
– 1
st
level: 2
e
-
– 2
nd
& 3
rd
levels: 8
e
-
– Valence shell =
outer shell
•
Octet rule
– Outer shell most stable when full
1
2
3
4
1
2
5
6
7
1
2
8
1
2
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2
– Note on ions
Assignment 1
•
Think, Pair, Share
•
Topic: Silicon (Si) has an atomic number of 14.

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- Fall '11
- TeresaFinnern
- Atom, polar covalent bond, (electron acceptor), (electron donor)
-
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