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Environmental Biology
Basic Chemistry
Basic Chemistry-The study of matter
Matter-Anything that takes up space (space + volume)
I.
Atoms
A. Definition: Smallest part of all matter

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The word Atom in Latin means Indivisible-unable to be
divided or separated
Not even a microscope can see an atom
An atom makes up a cell that are found in humans
All living and non-living things are MADE UP of Atoms
B. Composition:
 Sub-atomic particles
o Protons
o Neutrons
o Electrons
Subatomic
particle
Proton
Charge
Mass
Location
(+)
1 AMU
Nucleus
Neutron
(Neutral)
1 AMU
Nucleus
Electron
(-)
Almost Zero
Outside the
Nucleus
C. If Neutral Atom: #of Protons =#Electrons MUST be equal
C. Elements
a. Definition-substance that cannot be broken down into
other substances
Pure Element-Silver, Gold
b. Biologically important elements:
Major:
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorous
Minor:
Calcium
Iron
Magnesium
Potassium
a. Symbol:
Usually from the first letter or two of full name
Fe=Iron
K=Potassium
Mg-Magnesium
Ag-Silver
a. Atomic #-The number of Protons in a nucleus.
Atomic # is the most IMPORTANT number
because it defines the element.
b. Atomic mass / mass number
The total # of protons + neutrons in the
nucleus.
(EX): Carbon=6 Protons
Mass # is 14
How many neutrons does it have=8
c. IsotopesA form of the same element have the same number
of protons but different # of neutrons
Carbon 12-is the most abundant form of Carbon on
earth (made up of 6 protons and 6 neutrons)
Carbon 14-Is considered an Isotope. It decays and
gives off radiation.
Radio Active IsotopesAn isotope having an unstable
decomposes spontaneously
nucleus
that
Radioactive Isotopes are unstable and release
energy
Isotopes have a different number of neutrons than
protons
Example: Barium and Cat scans
Carbon Dating
Decoding Chemical Formulas
C6 H12 06=Chemical formula for Glucose or sugar
Carbon=(6) Hydrogen=(12) Oxygen=(6)
Chemical Compounds vs. Molecules
Molecules definition:
Two or more atoms held together by covalent bonds
Compound definition:
A substance containing two or more elements in a fixed ratio
Example: H20, Na+Cl

CO2=Carbon Dioxide
CO=Carbon Monoxide
c. Bonds
Covalent Bonds:
Atoms share electrons so
that both atoms fill their
outer energy level
O2=Oxygen
H2O-Oxygen is sharing electrons
with Hydrogen
Ionic Bonds: An electron transfers electrons becoming (+) or (-) charged
 Na+=Sodium
 Cl-=Chloride
=Salt
If something loses an electron it becomes
positive
Ions: An electrically charged atom
Water:
a. Human composition:
Cells are 70-90%
b. Plant composition:
About 95% can be made of water
c. Formula: H20
d. Bonds:
Hydrogen Bonds
Weak bond between Hydrogen and Oxygen

Weak attraction between (2) different water molecules
Covalent Bonds:
Shared electrons between Oxygen and Hydrogen (SHARING)
d. Water is a Polar molecule:
Definition of Polarity:
Opposite ends have opposite electric charges
Why?
Oxygen pulls electrons closer to it’s side than
Hydrogen. Oxygen becomes (-) and Hydrogen
becomes (+).
Water is a polar molecular because Oxygen is an
electron HOG. (Polar Covalent Hog)
e. Unique molecule:
Cohesion:
Definition:
Water sticks to each other
(b/c of Hydrogen bonds)
Example: Surface Tension
Adhesion:
Water molecules are also attracted to certain
other molecules.
Water molecules are attracted to the sides of
the trees roots and is able to move up.
Example: Capillary Action
In trees/plants water goes against gravity as the
water molecules are able to stick together
Solubility:
1. Water- is able to dissolve other polar
and ionic compounds when mixed by
causing the ions to break away and
surround them.
a. Universal solvent
Ex. Water dissolves salt
Water (polar) will not dissolve (non-polar) oil
Boiling point: water will boil at _100_ oC or
_212___oF
When you heat molecules they will move
faster
Freezing point: water will freeze at __0__oC
or __32___oF
d. Acids and Bases:
1. Acid Definition: pH 0-6
Example: HCl hydrochloric acid H+ ion and Cl2. Base definition:
 pH scale: scale of 0-14

Each pH unit represents a tenfold
change of H+ (Hydrogen Ions)