Crying with chem

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***