CHEMISTRY ATOMIC STRUCTURE

TERMINOLOGY Chemistry study of composition of matter and processes that build up and break down substances. Biochemistry study of chemical processes that help to sustain living things

3 SUBATOMIC PARTICLES Nucleus (Center) Positive protons Neutral neutrons Energy levels around nucleus Negative electrons Atoms are neutrally charged Protons (+) = Electrons (-)

PERIODIC TABLE

NUMBERS Atomic number: number of protons Protons identify the element Mass number: number of protons + neutrons Neutrons = mass number – protons

P=6 N=7 1st energy level = 2 2 nd energy level = 8 3 rd energy level = 18 Protons=Electrons P + N = Mass # Mass # - P = N

At. # P N E Mass # 8 ___ 8 ____ ___ __ ____ ___ 2 ___ ___ ____ 5 CALCULATIONS

ISOTOPES Same number of protons but different number of neutrons and different masses Atom: smallest unit of all matter Element: made of only 1 kind of atom

ISOTOPES Atoms have an atomic symbol, atomic number, and atomic mass.

VOCABULARY TERMS Molecule: 2 or more atoms chemical combined; smallest particle of a compound Compound: 2 or more different atoms chemically compound

BONDING Depends on arrangement and how many valence (outer) electrons Ionic Transfer of electrons between atoms Metals tend to lose (positive ions) and nonmetals tend to gain (negative ions)

Ions can have important biological functions.

BONDING Covalent Sharing of electrons between nonmetals (like atoms) Nonpolar covalent (equal sharing) Polar covalent (unequal sharing)

WATER Polar molecule Oxygen: greater attraction for electrons Slightly negative oxygen end Slightly positive hydrogen end

HYDROGEN BONDS Weaker bonds between water molecules Responsible for ability to form 4 hydrogen bond Cohesion: attraction between same substance (water)

PROPERTIES OF WATER DUE TO COVALENT BOND Surface tension: adhesion (different molecules) and cohesion (like molecules) Capillary action: movement of water up roots yer_detailpage&v=VHnFMPxteGohttp:// yer_detailpage&v=VHnFMPxteGo

CHARACTERISTICS OF WATER High specific heat: water warms and cools very slowly Biological importance: aquatic organisms are able to adjust slowly to the changing environment. Freezing: bonds expand and ice becomes less dense and will float Biological importance: top frozen layer helps insulate lake/pond

FREEZING Ice is less dense as a solid than as a liquid (ice floats) Frozen water forms a crystal-like lattice with molecules set at fixed distances.

High Heat of Vaporization Amount of energy to convert 1g or a substance from a liquid to a gas Hydrogen bonds must be broken so water evaporates and removes heat

Solutions & Suspensions Many things dissolve in water--the Universal Solvent Usually part of a mixture. Two types of mixtures: Solutions Suspensions Defn: material composed of 2 or more substances physically combined

SOLUTIONS Evenly distributed substances Solute: material dissolved Solvent: dissolving material Solute: salt Solvent: water

Suspensions Solute breaks up into pieces that will not settle out. Blood Plasma (liquid part) Dissolved compounds (solute)

ACIDS, BASES, pH pH: measures concentration of H scale Below 7: acidic 7: neutral Above 7: basic

ACIDS/BASES Acid: form H + in solution Bases: form OH - in solution

REVIEW Which bond is formed by the transfer of electrons between atoms? (Ionic) Which bond is the weakest and forms between water molecules? (hydrogen) Acids form ____ ions in solution. (H + --hydrogen ions) What is the solute? (material dissolved in solution)

WATER CHARACTERISTICS re=player_detailpage&v=0eNSnj4Zf Z8http:// re=player_detailpage&v=0eNSnj4Zf Z8

REVIEW What is adhesion? (attraction between molecules of different substances) What is the importance of capillary action? (pulls water into roots) Name the bond formed from unequal sharing of electrons. (polar covalent bond)