ScientifiC Process

1) every assertation regarding the natural world is subject to change

2)any scientific hypothesis must be falsifiable (open to negation through scientific inquiry)

3) scientific inquiry is only concerned with natural explanations for natural phenonama. not god or fairies

1) can assimilate (take in) energy

2) respond to environment

3) mantain a relatively constant internal environment

4) posses DNA 

5) can reproduce thru info in DNA

6) composed of one or more cells

7) evolved from other living things

8) highly organized compared to inanimate objects

living things are organized in a hierarchical manner (lower levels make up higher levels)

atom-molecule-organelle-cell-tissue-organ system-organism-population-community-ecosystem-biosphere

biologies chief unifying principle

the gradual modification of populations of living things over time

chemistries building block

composed of nuetrons, protons, electrons

make up molecules

"pure" cannot be reduced to any simpler set of component substances through chemical processes

defined by # of protons (atomic number)

various forms of elements due to variation of the number of nuetrons in an elements nucleus

carbon (normally has 6 p, 6 n. carbon 14, 8 n, 6 p)

Electrons reside in outer energy levels. 

2 electrons required to fill first energy level (shell)

8 required to fill every other energy shell. 

a chemical bond in which atoms share pairs of electrons

ex) H₂O; hydrogen shares its electrons w oxygens outer shell

no matter is gained or lost

atoms with filled outer shells are stable, do not want to bond

1- most reactive

8- least reactive

difference in electrical charge at one end of a molecule from another

more electrons on one end; more negatively charged

polar covalent bond

electrons are shared equally; methane, hydrogen bonds 

symmetric

a charged atom (has lost or gained an electron(s), therefore the number of electrons differs from the number of protons) 

ex) Na⁺if Sodium lost 1 electron, or if magnesium lost two electrons Mg²⁺

# of atoms of oxygen (O₂₎

# of molecules of atoms of Oxygen (3O₂₎

two dimensional representations of a given molecule.

single line = bond, represents one pair of electrons being shared

can explain ordering of atoms in a molecule, tell little about the 3 dimensional arrangements of atoms

better idea of molecular angles

spacefilling model; relative size, how they mold together

a collection of the atoms of two or more elements that have become linked through ionic bonding

NOT a molecule.

linked through ionic bonds NOT covalent

combine via electric attraction, do not physically share electrons 

covalently bonded hydrogen atom with an electronegative atom.

H almost always bonded w oxygen or nitrogen 

indicated by a dotted line

relatively weak compare to ionic/covalent

 constantly breaking and reforming (h bonds close together in liquid water), (in ice they sit far apart because maximum # of bonds reached, therefore less dense)

heat=motion of molecules...

to move molecules bonds most be broken...

water has a lot of H bonds, requires lots of energy to break those bonds

humans are 66% water by weight 

living things are not functional without water

 great solvent because polar and therefore keep ions evenly dispersed, and ability to form hydrogen bonds

a mixture of two or more molecules, atoms, ions that is homegeneous throughout

cannot be dissolved aka methane

no electrical charge, water doesnt want to bond

power of Hydrogen

measures the relative acidity of a substance

based off of concentration of H⁺ ions in solution

0- most acidic, 14- most basic, 7- nuetral

logarithmic; pH of 9 is 10 times as basic as 8, 100 times more basic as 7

YEILDS h atoms when put in an aqueous solution.

acidic solution has a higher concentration of H+ ions 

accepts hydrogen atoms in an aqueous solution

basic solution also reffered to as a alkaline solution