Gerente

8/22/11
Chemistry - the study of matter
Matter - anything that takes up space (gas, solid liquid)
-periodic table - arranged in patterns/cycles
-chemical symbols - first letter capitalized, second letter = true lowercase
8/26/11; 8/30/11
-Scientific notation - makes big and small numbers easier to read and understand
-Significant figures = Sig figs
-only pertains to measured numbers
                                      decimal point
Pacific = present  Atlantic = absent
If the decimal point is present then you start from the left and count the number of numbers
If the decimal point is absent then you start on the right and start counting from the first number that is not 0
Multiplication/Division:
-round to the least number of significant figures
-rounding = (0-4) -> 0 ;(5-9) -> +1
Adding/Subtraction:
-count the decimal places not number of significant figures
 
V = l x w x h
1 cm3 = 1 ml
1 dm3 = 1 liter
-density = mass/volume or g/ml or g/cm3
 
-ductility - drawing a metal out into wires
Extensive Properties - depend upon the amount of the substance (ie mass, volume)
Intensive Properties - do not depend upon the amount of substance (ie odor,melting point, ductility, density)
 
8/29/11
Precision vs. Accuracy
Precision - the ability to reproduce a measurement
Accuracy - how close you are to the true value
 
9/12/11
-period - cyclical pattern
-elements - distinguished by their numbers of protons
         -off [differ] by whole number integers
         -Mosley (British scientist) discovered this
 
Atom:
-JJ Thompson - plumpudding (scattered electrons)
-Rutherford - discovered a dense center that deflected alpha rays
-nucleus: protons and neutrons (which determine the mass)
-there can be up to 8 electrons in the outer shells (and 2 in the innermost shell)
E - number = carbon-14
-metals - tend to lose electrons (on the left of the periodic table; majority)
-nonmetals - tend to gain electrons (on the right of theperiodic table and hydrogen)
 
11p       +11                           11p       +11
11e        -11                           10e        -10
                 0                                           +1
 
-net charge of an element always = 0
 
 
 
-valence = outer electrons
-atoms - always want a full outer shell (octet=8) for stability and low energy
-all ions = aqueous solution (wateris the solvent) [no such thing as an ion solid or gas
-ion - unequal distribution of charge (has a net charge); has gained or lost an electron
-sodium - never in elemental form because it is highly reactive = you find it combined
F - nonmetal, highly reactive, wants to gain 1 electron
-cation - positive ion
-anion - negative ion
-ions - more stable
-diatomic gases (stable structure = F2)F, N, O, H, Cl, Br, I
Metals - man, comes first in the nomenclature of ionic compounds
Nonmetals - woman, comes second in the nomenclature of ionic compounds
alloy - mixed metals
nonmetals - usually anions (-)
metals - usually cations (+)
 
9/13/11
-ionic compounds = solid at room temperature, dissolve in water
         -binary: 2 kinds of atoms
         -ternary: 3 kinds of atoms
-thealgebraic sum of ions in an ionic compound has to equal zero
representative elements - groups 1-8
-every element in a column has the same charge
-transition metals - middle groups
-monatomic negative ions always end in –ide (Cl- = chloride)
-halogens: group 7 (all have -1 charge)
-alkali: group 1 (all have +1 charge)
-group 2 = +2 charge
-group 6 (exc. Po) = -2 charge
-group 5 (N, P, Asonly) = -3 charge (only up to the ‘staircase’)
transition elements - some of the ions can have more than one possible charge
NaCl  -charges are implied - no subscripts implies 1 atom of each
-formulas for ionic compounds must be empirical (in simplest whole number ratio)
 
9/14/11
Charges -
-1 = group VII - halogens
-2 = group VI - chalcogens
-3 = group V - pnicogens
Binary - has 2...