Studied by 3 people
3 reasons for big bang
the measured abundances of elements, the observed expansion of space, and the discovery of the cosmic microwave background
Red shifted
moving away
Blueshifted
moving towards
atomic emission spectra
the set of frequencies of the electromagnetic waves emitted by atoms of the element
protons
positively charged particles in the nucleus of an atom
Proton mass
1 amu
Neutron mass
1 amu
Neutron
no charge, in nucleus
Electron mass
0 amu
Electron
negatively charged particle outside the nucleus
nuclear decay
a process that occurs when an unstable atomic nucleus changes into another more stable nucleus by emitting radiation
Half life
length of time required for half of the radioactive atoms in a sample to decay
How to find half life on decay graph
Take half of the initial mass go across until the line meets the curve. Then go down to find the time that corresponds to the half life.
isotopes
Atoms of the same element that have different numbers of neutrons
average atomic mass
the weighted average of the atomic masses of the naturally occurring isotopes of an element
how to calculate average atomic mass
Divide percents of naturally occurring isotopes by 100, multiply percent by mass, add all together.
Subscripts
number of electrons in a given sublevel
Number and letters in electron configuration
two of the electron's four quantum numbers., tell us more information about the properties of electrons and their orbitals.
three rules to follow when drawing an energy level diagram
Aufbau Principle, Pauli-exclusion Principle, and Hund's Rule
Aufbau Principle
An electron occupies the lowest-energy orbital that can receive it
Pauli-exclusion Principle
An atomic orbital may describe at most two electrons, each with opposite spin direction
Hund's Rule
electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible
Matter breaks down into
pure substances and mixtures
Mixture breaks down to
Homo and Heterogenious mixtures
homogeneous
of the same kind
heterogeneous
(adj.) composed of different kinds, diverse
Pure substances breaks into
Compound and elements
chemical chage
substance combines with another to form a new substance
physical change
a change of matter from one form to another without a change in chemical properties
four pieces of evidence for a chemical reaction
color change, formation of a precipitate, formation of a gas, odor change, temperature change
5 kinds of chemical reactions
single displacement, double displacement, combustion, synthesis, and decomposition
single displacement
A + BC --> AC + B
double displacement
AB + CD --> AD + CB
combustion
the process of burning something
synthesis
combining parts into a whole
decomposition
AB->A+B
Four Intermolecular Forces (weakest to strongest)
dispersion force.
Dipole-dipole force.
ttractive forces between the positive end of one polar molecule and the negative end of another polar molecule.
Hydrogen bond.
a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.
Ion-dipole force.
an attractive force that results from the electrostatic attraction between an ion and a neutral molecule that has a dipole
dispersion force
attractions between molecules caused by the electron motion on one molecule affecting the electron motion on the other through electrical forces; these are the weakest interactions between molecules
Dipole-dipole force
attractions between oppositely charged regions of polar molecules
Hydrogen bond.
weak attraction between a hydrogen atom and another atom
Ion-dipole force.
an intermolecular force between an ion and the oppositely charged end of a polar molecule
Gas laws
the laws that state the mathematical relationships between the volume, temperature, pressure, and quantity of a gas
first law of thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed.
second law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe.
Specific heat
The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius
How to find Neutrons
Mass-atomic number
How to find protons
Equal to the atomic number
How to find electrons
Electrons are equal to number of protons
What is the 6
Atomic number
12.011
Atomic mass
WHat is the 7
protons+neutrons
What is the 3
Protons
Polar
uneven distribution of electron density
Nonpolar
one whose charge distribution is spherically symmetric when averaged over time
Ionic
compounds made up of ions that form charged particles when an atom (or group of atoms) gains or loses electrons
Covalent
chemical bond that involves the sharing of electrons to form electron pairs between atoms
