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Shannon Morgan

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Period 6

I. Basic ChemistryA. Elements and Atoms

1. all matter composed of elements2. carbon, hydrogen, nitrogen, oxygen, phosphorus, & sulfur make up 98% of

body weight of organisms

3. atom - smallest unit of matter

4. have a central nucleus - protons and neutrons located here & electrons on

outside orbitals

5. atom stable when outter shell has 8 electrons

6. atomic number = number of protons

B. Isotopes

1. atomic mass = number of protons plus neutrons

2. atoms with same atomic number & only differ in number of neutrons = isotopeex: carbon 12, c13, c14

3. c14 is radioactive, radioactive isotope - unsttable form of an atom that

spontaneously emits radiation in the form of radioactive particles or radiant energy

C. Molecules and Compounds

1. molecule - atoms bond with eachother to form chemical unit

2. compound - different atoms combine together

3. two types of bonding: covalent and ionic4. covalent - sharing electrons

5. ionic - giving/taking electrons

6. ions - particles that carry either a positive or negative charge

7. double and triple bonds - share only a pair of electrons

8. stronger than single bonds

9. molecules have three-dimensional shape

10. shape necessary to the structural and functional roles in living things

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II. Water and Living things

A. Water and Living things

1. most abundant molecule

2. electrons spend more time circling larger oxygen than smaller hydrogen

3. oxygen gives slight negative charge, hydrogen gives slight positive charge

B. Hydrogen bonds

1. occurs when covalently bonded hydrogen is positive & attracted to negatively

charged atom

2. represented by a dotted line

3. weak and can be easily broken

C. Properties of Water

1. cohesive because of polarity and hydrogen bonding

2. water is liquid at room temperature

3. compounds with low molecular mass usually gases at room temperature

4. hydrogen bonding keeps h2o liquid at room temperature

5. ions and molecules that intereact with water are hydrophilic

6. temp. of liquid water rises and falls slowly, no drastic changes

7. frozen water less dense, ice floats on water

D. Acidic and Basic Solutions

1. acids - molecules that dissociate in water, releasing hydrogen ions (H+)

2. basics - take up H+ or release hydroxide ions (OH-)

3. litmus test - dye changes red to blue based on acidity

E. The pH Scale1. measues acidity or basicity (alkalinity) of a solution

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2. 0-14 scale

3. 0-7 is acidic

4. 7-14 is basic

5. each unit has ten times H+ as previous

6. buffer - chemical or combination of chemicals that keep pH in normal limits