Final Exam Review Flashcards
composition
what something is made of
structure
what something is made of and how the components are arranged
pure substances
elements and compounds
atom
the fundamental unit of matter
element
made of only one type of atom
compounds
composed of more than one element, bound in fixed ratios
molecules
groups of atoms that bind tightly together and behave as a single unit
mixture
contain more than one substance but not bound in a fixed ratio
homogeneous mixture
compounds mix evenly
ex. air
heterogeneous mixture
components do not mix evenly
ex. sand separates from water; cookie dough
solid
definite shape and volume
liquid
definite volume but no definite shape
gas
no definite shape or volume
chemical properties
can NOT be measured without changing the identity of the substance
chemical changes
chemical reactions; change the identity of the substance
physical properties
can be measured without changing the identity of the substance
physical changes
don’t change the identity of the substance
exothermic change
releases heat energy
endothermic change
absorbs heat energy
scientific method
make an observation, formulate new ideas, test ideas with experiments
hypothesis
a tentative explanation that has not been tested
theory
how or why it happens (supported by experimental evidence)
law
what happens (statement that describes observations that are true)
scientific notation moving decimal right
negative exponent
scientific notation moving decimal left
positive exponent
scientific notation multiplication
multiply coefficients and add the exponents
scientific notation division
divide coefficients and subtract exponents
accuracy vs. precision
accuracy: how reliable are the measurements
precision: how closely are the measurements made / how finely are the measurements
significant digits
-nonzeros
-zeros between nonzeros
-zeros after the decimal point
not significant digits
zeros to the left of all nonzeros
how to convert between units
1) write out the two conversion factors
2) set up the problem to cancel units
micro
10^-6
milli
10^-3
centi
10^-2
kilo
10^3
1 mL =
1 cm^3
1 L =
1 dm^3
1 m^3 =
1,000 dm^3
boiling and freezing points of water in Celsius
100 and 0
density =
mass / volume
Democritus
first proposed atoms
Lavoisier
Law of Conservation of Mass
Dalton
atomic theory
Mendeleev
periodic table
Thomson
discovered the electron
Rutherford
showed that atoms are mostly empty space with a small, dense nucleus
Bohr
proposed the Bohr model
Law of Conservation of Mass
in chemical reactions, matter is neither created or destroyed
proton mass, charge, and location
m: 1.0073
c: +1
l: nucleus
neutron mass, charge, and location
m: 1.0087
c: no charge
l: nucleus
electron mass, charge, and location
m: 0.0005
c: -1
l: around the nucleus
atomic number
-number of protons in an atom
-number of electrons in a neutral atom
mass number
the number of protons and neutrons
isotopes
have the same atomic number but a different mass
writing atomic symbols
top left: mass number = p+n
bottom left: atomic number = p
how to calculate average atomic mass
(value A x fraction A) + (value B x fraction B)
group 1A (column 1)
alkali metals
group 2A (column 2)
alkaline earth metals
group 7A (column 17)
halogens
group 8 A (column 18)
noble gases
transition elements
columns 3-12
pure metals
columns 1-2
nonmetals
upper right side (plus H)
metalloids
stairstep between metals and nonmetals
inner transition elements
two rows on the bottom of the periodic table
line spectra of atoms
occurs when gases are passed through a prism; each element produces a unique line spectrum
white light passed through a prism results in the full spectrum of the rainbow
how do atoms absorb or emit light energy
by electrons rising or falling to different energy levels
how many electrons fit in level 1
2
how many electrons fit in level 2
8
how many electrons fit in level 3
18
how many electrons fit in level 4
32
quantum mechanics
describes electrons most probable locations and energies
s subshell
1 orbital
2 electrons
p subshell
3 orbitals
6 electrons
d subshell
5 orbitals
10 electrons
f subshell
7 orbitals
14 electrons
electron capacity =
of orbitals x 2
significant figures addition and subtraction
round to the last decimal place of the least precise starting measurement
significant figures multiplying and dividing
same number of digits that are in the least precise measurement
E = ?
Planck’s constant x speed of light / wavelength
how to determine the number of protons and electrons in an atom using the periodic table
atomic number
how to determine the number of valence electrons using the periodic table
group number (group = vertical)
electron configuration and the periodic table:
1. row indicates…
2. column gives…
- row: highest occupied electron energy level
- column: outermost electron configuration
cation
positive charge
anion
negative charge
isoelectronic
same number of electrons
s, p, d, f blocks
sdpf
s: column 1-2
p: everything right of the transition metals
d: transitions metals
f: lower periods
ionic bonds occur between…
oppositely charged ions
positive charges must equal the negative charges