CHEMISTRY

ATOMIC STRUCTURE

TERMINOLOGY

Chemistry study of compositionof 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=6N=7

1st energy level = 22nd energy level = 83rd energy level = 18

Protons=ElectronsP + N = Mass #Mass # - P = N

At. # P N E Mass #

8 ___ 8 ____ ___ __ 12 13 ____ ___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

• http://www.youtube.com/watch?feature=player_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+

• 1-14 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

• http://www.youtube.com/watch?feature=player_detailpage&v=0eNSnj4ZfZ8

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)