1. Biology
Basic Chemistry

2. Matter and Atomic Structure
Atom: the smallest particle of an element; consists of:
Protons p+: in the nucleus
Neutrons no: in the nucleus
Electrons e-: surrounds the nucleus; equal to the number of protons

3. Matter and Atomic Structure
Matter: anything that has volume and mass
Element: a substance not broken down into simpler substances by physical or chemical means
Each element has a 1 or 2-letter symbol
Examples: oxygen (O), sodium (Na)
Molecule:A molecule is formed when two or more atoms join together chemically.
Ex: hydrogen (H2), oxygen (O2) and nitrogen (N2)
Compound: a molecule composed of atoms of 2+ different elements that are chemically combined
Ex: NaCl: salt, H2O: water

4. Matter and Atomic Structure
Atomic Number: the number of protons in an atom’s nucleus
Mass Number: the number of protons and neutrons in an atom
Energy levels: the area of an atom surrounding the nucleus where electrons are found
# of protons always equals the # of electrons; atoms have NO CHARGE

5. Energy Levels First energy level: holds up to 2 electrons
Second energy level: holds up to 8 electrons

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Chemical Bonds
The main types of chemical bonds are:
ionic bonds
covalent bonds
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Chemical Bonds
Ionic Bonds
An ionic bond is formed when one or more electrons are transferred from one atom to another.
These positively and negatively charged atoms are known as ions.
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Chemical Bonds
Sodium atom (Na)
Sodium ion (Cl-)
The chemical bond in which electrons are transferred from one atom to another is called an ionic bond. The compound sodium chloride forms when sodium loses its valence electron to chlorine.
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Chemical Bonds
Covalent Bonds
Sometimes electrons are shared by atoms instead of being transferred.
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Chemical Bonds
A covalent bond forms when electrons are shared between atoms.
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Chemical Bonds
The structure that results when atoms are joined together by covalent bonds is called a molecule.
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Water
About percent of an organism is water
Water is used in most reactions in the body
Water is called the universal solvent
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The Water Molecule
Water Molecule
The unequal sharing of electrons causes the water molecule to be polar. The hydrogen end of the molecule is slightly positive and the oxygen end is slightly negative.
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Water Properties
Polarity
Cohesiveness
Adhesiveness
Surface Tension
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The Water Molecule
A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms.
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The Water Molecule
Hydrogen Bonds
Because of their partial positive and negative charges, polar molecules can attract each other.
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The Water Molecule
Cohesion is an attraction between molecules of the same substance.
Because of hydrogen bonding, water is extremely cohesive.
Example: surface tension (bugs walking on water)
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The Water Molecule
Adhesion is an attraction between molecules of different substances.
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19. Solutions and Suspensions
A mixture is a material composed of two or more elements or compounds that are physically mixed but not chemically combined.
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20. Solutions and Suspensions
Two types of mixtures can be made with water
solutions
suspensions
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21. Solutions and Suspensions
All the components of a solution are evenly distributed throughout the solution.
solute—the substance that is dissolved.
solvent—the substance in which the solute dissolves.
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22. Solutions and Suspensions
When a crystal of table salt is placed in warm water, sodium and chloride ions are attracted to the polar water molecules.
Na+
Cl -
Water
When an ionic compound such as sodium chloride is placed in water, water molecules surround and separate the positive and negative ions.
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23. Solutions and Suspensions
Some materials do not dissolve when placed in water but separate into pieces so small that they do not settle out easily.
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24. Acids & Bases
Acid: any compound that forms H+ ions in solution
Base: any compound that forms OH- in solution
Water can dissociate to form acids and bases
H H+ + OH-

25. pH Scale
A measurement system indicating concentration of H+ or OH- ions in a solution
Ranges from 0-14
= acidic solution
0 more acidic than 6.99
= basic solution (alkaline)
14 more basic than 7.1

26. **This scale can be presented 0-14 OR 14-0**
**This scale can be presented 0-14 OR 14-0**