Unit 1 Flashcards
Protons=
positive
atomic number
in the nucleus
Electrons=
negative
atomic number
Neutrons=
neutral
in the nucleus
Atomic Mass
protons + neutrons
You go right on the periodic table
gets smaller, gain more electrons and protons so its a greater attraction force
You go down the periodic table
gets bigger, theres more electrons and protons BUT theres more orbits so it gets bigger
How many atoms of hydrogen are found in the sample of methane (2.71*10^23 particles CH4
1.08*10^24 atoms H
Isotopes
same number of protons as the normal element, but different number of neutrons. So they will have a different mass
Mass Spectrum
a graph that shows the different isotopes and how much is present
Relative abundance
tells us how common an isotope is in the sample.
Average atomic mass
(the relative abundance * mass) + (relative abundance * mass) + (relative abundance * mass)
ex- #85 has NA of 72.17% and mass of 84.912
#87 has NA of 27.83% and mass of 86.909 what is the third mystery element
hint make sure to move to decimal in the percentage (left)
One atom
ex- Mg
any
described as atom
More than one element (ionic)
ex- NaCl or Fe(NO3)2
Metal + Nonmetal
described as formula unit
More than one element (covalent)
ex- H2O or O2 or C6H12O6
Nonmetal +Nonmetal
described as molecule
Atom or group of atoms with a charge
ex- Pb2+ or SO4 2-
any
describes as ion
Compound
A substance compose of two or more elements united chemically in definite proportions.
Mixture
A combination of two or more substances in which each substance retains its own chemical identity.
Law of Constant Composition
A law that states that the elemental composition of a pure compound is always the same, regardless of its source; also called the law of definite proportions.
Heterogeneous Mixture
A mixture which does not have the same composition, properties, and appearance throughout.
Homogeneous Mixture
A mixture which has uniform composition, properties, and appearance throughout.
Solution
A mixture of substances that has a uniform composition; a homogeneous mixture.
Kelvin Scale
The absolute temperature scale; the SI unit for temperature.
Density triangle formula
M
D V
Precision
The closeness of agreement among several measurements of the same quantity; the reproducibility of a measurement.
consistency, reliable results, reproducibility
Accuracy
A measure of how closely individual measurements agree with the correct value.
Sig Figs
1- 10082
2- 70,000
3- 0.0025
4- 50010.000
5- 0.0040030
1- 5 sig figs
2- 1 sig fig
3- 2 sig figs
4-8 sig figs
5- 5 sig figs
Only trailing zeros are important (if decimal)
Empirical Formula
ex- 41.368% C, 8.101% H, 32.162%N, and 18.369% O
the simplest ratio of elements in a compound.
you need to divide each elements percentage by their atomic mass and then which ever is the smallest one, you take that and divide each answer by that. Then make the new formula
C3H7N2O
Percent Composition
formula= (mass of that element) / (mass of compound) *100
then you can find empirical formula
What is a mixture
combination of two or more pure substances (elements or compounds)
what is stoichiometry
converting moles and masses
mass percentage
(mass of substance / total mass of mixture) * 100
what is elemental analysis
element mass/compund mass
what are the two types of elemental analysis
- qualitative (identifying the different elements present)
- quantitative (identifying the amounts of elements present
what is CHNX analysis
mathod to determine the mass fractions of C, H, N or sulfur in a compound
combustion analysis
a technique where a sample is burned to convert its C, H, N, and sulfur into their respective oxides
optical spectroscopy
technique that measures the absorption or transmission of light through a solution to determine its concentration
mass spectroscopy
tequnique used to determine the charge to mass ratio of ions by ionizing a sample then passing them through a magnetic field which separates them based on mass and charg, then this detector measures number of ions and mass to ion ratio
photoelectron spectroscopy
technique used to measure the energy requried to remove electrons from atoms to determine their electron configuration
isotopes
variation of the same element with different numbers of neutrons
(same protons and electrons)
How do you convert moles to number of particles and vise versa
Avogadros number
6.022*10^23
Avogadros number
6.022*10^23
How do you convert mass to moles and vise versa
atoms mass
one atom
what is it made from?
ANY (nonmetal, metal, gas, liquid anything)
One atom examples
Mg, O, Zn, Ne
More than one element (ionic)
metal+nonmetal (s)
NaCl, Fe(NO3)2
IONIC
How do you describe ionic compounds
Formula unit
More than one element (molecular)
nonmetal+nonmetal (s)
H2O, C6H12O6,O2
MOLECULAR
how do you describe molecular compounds
molecule
atom or group of atoms with a charge is made from
any (nonmetal+metal, nonmetal+nonmetal, metal, nonmetal)
How do you describe atom or group of atoms with a charge
Ion
Energy level 1
s
2 electrons
Energy level 2
sp
8 electrons
Energy level 3
spd
18 electrons
Energy level 4
spdf
31 electrons
Coulombs law
higher charges and smaller distance= more attraction
Aufbau principle
means to “build up” electrons are added to the lowest subshells first and build up
Hund’s rule
each subshell should have one electron before any are doubled up (dont share space unless they have to)
Pauli Exclusion Principle
no two electrons can have the same set of 4 quantum numbers
what does a photoelectron spectroscopy do
shows the electron configuration
octet exceptions
Be, B, N, O
ionic compounds are held together by??
an electrostatic force
will 2 metals bond?
nope
