CHEMISTRY
Mrs. Ogburn
AP Biology
C202
OF
LIFE
Why are we studying chemistry?
Chemistry is the foundation of Biology
ATOM
BASIC UNIT OF MATTER
• Subatomic particles
• Protons (+) : nucleus
• Neutrons (=) : nucleus
• Electrons (-) : electron shells/energy levels
Atoms are neutral
Proton # = Electron #
ELEMENT
PURE SUBSTANCE, 1 TYPE OF ATOM
• Atomic Number = Proton # (& Electron #)
• Atomic Mass = Protons + Neutrons
ELEMENT
PURE SUBSTANCE, 1 TYPE OF ATOM
ELEMENT
PURE SUBSTANCE, 1 TYPE OF ATOM
• Atomic Number = Proton # (& Electron #)
• Atomic Mass = Protons + Neutrons
ELEMENT
PURE SUBSTANCE, 1 TYPE OF ATOM
4 elements make up 96% of the human body
CARBON
HYDROGEN
OXYGEN
NITROGEN
ELEMENT
PURE SUBSTANCE, 1 TYPE OF ATOM
Living organisms are mostly made of these 6 elements
CHNOPS
ISOTOPES
SAME ELEMENT, DIFFERENT NEUTRON #
• Same E- #
• Same chemical properties
• Different Neutron #
• Different atomic masses
ATOM
BASIC UNIT OF MATTER
• Atoms want their outer energy levels stable
• Outer energy level = valence shell
• How many valence electrons are needed to fill the outer
valence shell of each atom?
CHEMICAL BONDS
HOLD TOGETHER ATOMS IN COMPOUNDS
Compound = element + element + element
H2O
NaCl
IONIC BONDS
ELECTRONS ARE MOVED; WEAK
• Chemical bond where atoms give up or accept
an E- to form a compound (Ionic Compound)
• When atoms gain or lose E-, they become
charged particles (Ions)
• Weak, easily broken
COVALENT BONDS
ELECTRONS ARE SHARED; STRONG
• Chemical bond where atoms share E- to form
a compound (Molecule)
• Strong
WATER IS POLAR
POLARITY
• Polarity - Uneven distribution of E- between
the oxygen and hydrogen atoms
• Oxygen end is slightly –
• Hydrogen end is slightly +
WATER IS COHESIVE
COHESION
• Cohesion – attraction between molecules
of the same substance
• Hydrogen Bonds (very weak)
• Water molecules can bond together
through Hydrogen Bonding
• Surface Tension – force that results from
the strong attraction b/w water molecules
which can support very light objects.
http://www.sciencedump.com/content/pygmy-gecko-can-walk-water
SOLUTION
SUBSTANCES EVENLY DISTRIBUTED
• Solute – substance that is dissolved
• Sugar
• Salt
• Solvent – substance in which the solute
dissolves
WATER is the greatest solvent on earth
• ______
• Carries nutrients
• Removes wastes
WATER
•
•
•
•
•
Polar compound
Hydrogen bonding
Cohesion
Adhesion
Capillary action
• Universal solvent
– carries nutrients
– removes wastes
• Most abundant
substance in body
• Needed for digestion
• Regulates
temperature
PH
0
0
7
14
ACIDS
7
BASES
14
• Acids (acidic)
• Less than pH of 7
• Hydrogen ion (H+)
• Water
• pH of 7
• neutral
• Bases (alkaline)
• Greater than pH of 7
• Hydroxide ion (OH-)
PH
0
ACIDS
7
BASES
14
Relative concentrations of Hydrogen and Hydroxide ions
Acidic
Alkaline
Crash Course over pH: http://youtu.be/LS67vS10O5Y