Studied by 309 peoplewhat are three lab safety rules
no food or drink in lab, wear safety gear, no sitting on the tables
what are the rules for zeros related to significant figures
all numbers other than 0 are significant, if zero is the last number after the decimal point it is significant and all 0's between sig figs are significant
when is a zero not significant
when it is a place holder (ex. 400)
metric prefixes largest to smallest
mega, kilo, hecto, deka, standard(m,g,l), deci, centi, milli, micro, nano
define homogeneous
mixtures that are uniform in composition
ex. of homogeneous mixture
water
define heterogeneous
mixtures that are not uniform throughout
ex. of heterogeneous mixture
chunky peanut butter
intensive property
a property where size doesn't matter because whats in a small piece is the same in a big piece
ex. of intensive property
color, density, melting point, conductivity
physical change
the appearance or form of the matter changes but the kind of matter doesn't
examples of physical change
cutting, bending, freezing, dissolving, boiling, melting
chemical change
when one or more substances change into a new substance
ex. of chemical change
iron rusting, wood burning
define extensive property
the size matters, the difference between a big and small piece
example of extensive property
height, weight, length, volume,
what is a mixture
two or more substances that aren't chemically combined
examples of mixtures
koolaid, salt water, air
what is a compound
two or more atoms in a set ratio
examples of a compound
glucose (C6H12O6), peroxide (H2O2), water (H2O)
what law did Lavoisier propose
he proposed the Law of Conservation of Mass
what does the Law of Definite Proportions state
matter combines in set ratios by mass and elements combine in set rations by mass
what does the Law of Multiple Proportions state
elements combine in small whole number ratios
what does the Law of Conservation of Mass state
matter can neither be created nor destroyed
what subatomic particle did JJ Thomson discover
electrons
what did JJ Thomson use to discover electrons
cathode ray tube
what was the gold foil experiment
it measured how an alpha particle beam is scattered when it strikes a thin metal foil
what was learned from the gold foil experiment
atoms are mainly empty space and there must be a tiny center that is heavy (nucleus)
what was learned about the nucleus in the gold foil experiment
it is positively charged
what is an elements atomic number
the number of protons in the element
what is an elements mass number
the number of protons and neutrons
what is an isotope
atoms of the same element with same number of protons but different number of neutrons (causing different masses)
mass of protons and nuetrons
1
mass of electron
0
what does the principle quantum number represent
size of energy level where the electron is located
what is an octet
s^2p^6
what are valence electrons
the electrons in the outermost level/ending of an electron configuration
what is the number of valence electrons most elements want to acquire
8 electrons
what is the importance of s^2p^6
it represents the ending electron configuration that elements need to be the most stable
what is the Pauli Exclusion Principle
no two electrons in the same atom can have the same set of quantum numbers
what is Hund's rule
place one electron in each orbital before paring them up
what happens when electrons become excited
they jump out to the next energy level
what happens when an excited electron is returning to its ground state
it releases the excess energy by emitting light
what does ROYGBIV represent
red, orange, yellow, green, blue, indigo, violet
at what end of ROYGBIV are the wavelengths the longest with the lowest energy
red
at what end of ROYGBIV are the wavelengths the shortest with the highest energy
violet
what is the Aufbau principle
place electrons in the lowest energy level first
what are the three categories that elements are divided into
metals, non-metals and metalloids
most elements on the periodic table are in which category
metals
do metals gain or lose electrons to become more stable
lose electrons
do non-metals gain or lose electrons to become more stable
gain electrons
what is a metalloid
an element who has metal and nonmetal properties
where are metalloids found on the periodic table
the stair steps
what is special about noble gases
they are already stabilized and have an octet
what group is noble gases in
group 18
what is electronegativity
the attraction for an additional electron
what is the most reactive nonmetal
fluorine (F)
what is the least reactive metal
francium (Fr)
what is the periodic trend in atomic radii as you move down a group
the radii increases as you go down
what group is halogens
group 17
what group is alkali metals
group 1
how did Mendeleev arrange his elements in the first periodic table
by their properties
what is the periodic trend for ionization energy
increases going left to right, decreases going top to bottom
what is the periodic trend for atomic radii
decreases going left to right and increases going top to bottom
what is the periodic trend for electronegativity
increases going left to right and decreases going top to bottom
what is the periodic trend for atomic mass
it increases going both top to bottom and left to right
ammonium
NH4
carbonate
CO3
hydroxide
OH
sulfate
SO4
phosphate
PO4
nitrate
NO3
when writing/naming compounds, which ion goes first
positive ion(cation)
when naming a binary compound what three letters will the name end with
ide
mono
1
di
2
tri
3
tetra
4
penta
5
hexa
6
hepta
7
octa
8
nona
9
deca
10
what is the rule when naming compounds with prefixes
only use a prefix on the first element if has more than one atom
what is the criss cross technique for writing formulas
if the charges dont add up to 0 then criss cross them and write them for the subscripts of the opposite element
what is the empirical formula
the simplest whole number ratio of a compound
definition of mole
the amount of a substance that contains as many particles as there are atoms in 12g of Carbon-12
define stoichiometry
the mass relationships between reactants and products in a chemical reaction
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