Chemistry- Unit 2 – Ch. 3+4

Who is Democritus
-A greek philosopher
-founded atoms
– “atoms cant be created, destroyed, or divided”
-His theory was rejected by aristotle
Who is Aristotle
-Briliant Greek philosopher
-everyone believed him
-did accept Democritus Atomic Theory
Who is Dalton

-recreated Democritus’s theory

-father of chemistry

-had 5 pt theory called “—-‘s Atomic theory”

Who is Sir William Crookes
-did cathode ray experiment
-found all matter had negative particles
Who is JJ Thompson
-mathmatically proved cathode ray
-found first electron
Who is Robert Millikan
-known for oil drop experiment
-found charge and mass of electron
Who is Ernest Rutherford
-known for Gold foil Experiment
-Found nucleus and proton
Who is James Chadwick
-found neutron which had no charge
Who is Henry Moseley
-said all things have different # of protons
-protons identify element
Who is Max Planck
-wanted to know why some colors burned to different colors
-found quanta
-has his own constant
-found matter can gain and lose energy
who is Niels Bohr
-young danish physicist
-mathmatically tried to find why emmision spectrum was discontinued
-math only worked for hydrogen
who is Louis De Broglie
-young french grad student
– tweeked bohrs math
-found electrons are a duality
who is Weiner Heisenberg
-german physicist
-tried to measure and electron w/o moving it
-found his uncertainty principle
who is Erwin Schrodinger
-austrian physicist
-the man of quantum mechanics
-fixed all bohrs math
what is Democritus’ atomic theory
-“atoms cant be created, destroyed, or divided and matter is composed of empty space where atoms move”
-aristotle rejected his concept
What is Daltons atomic theory
1-matter is composed of small particles called atoms
2-atoms cant be created divided or destroyed
3- atoms of given elements are identical
4-atoms combine in simple whole number ratios to form compounds
-in chem reactions, atoms seperate, combine or rearrange
-only thing wrong: atoms can be divided nuclear-ly
-raised more questions than answers
what is an atom
smallest particle of element that retains properties of that element
What is the cathode ray experiment
this is when crookes filled a tube with only argon and noticed there were rays going from the cathode to the anode. this concluded that all matter had negative particles
what is an electrode
a tube with 2 ends
what is the anode and cathode
anode is the postive and cathode is the negative
what is an electron
negative charged particle that exists in all matter
-the charge is e to the -1
What is the plum pudding model
thompsons theory stated that the plums were electrons and and the pudding is a uniform positive charge.
What is the gold foil experiment
took alpha partices and shot it through foil.
rutherford thought it would go through if there was nothing there, shoot out if it hit a proton, and stick if it had a electron
found it went straight back out when it hit the middle and went out sides when it hit the off middle. this found the nucleus
what is a nucleus
tiny dense region with more than 99% of mass in it
what is a proton
positive charged particle that exists in all matter
what is a neutron
no charge particle in the nucleus
What is an isotope
same number of protons but different number of neutrons
how do u find the isotope mass
protons + neutrons

mass number: 1.008

atomic number: 1


P- 92

E- 92

N- 146

what is abundance
how common something is
what is atomic mass
weighted average mass of isotopes
C-12 and c-14, which is more abundant and why?
c-12, because it is closer to the real mass on the periodic table
what is the isotope mass equation
mass * (% abundance)/100 + …
what is a nuclear reaction
atom of 1 element changes into an atom of another element
what is a gigeer counter
used to measure radiation
what is radiation
rays and particles emitted by radioactive material.
-stuff that shoots off of something
what is radioactive
substance spontaneously emits radiation
-act of radiation
-caused by an unstable nucleus
radioactive decay
unstable nucleus loses energy by emitting radiation to form a new element
-postive charge and atttracted to negative
-not good but least harmful
-naturally exists
-skin protects you
-helium nucleus
-medium dangerous
-negative charge and attracted to positive
-clothes protect you
-high speed electron
-least mass
-no charge and no mass
-VERY dangerous
-protected by lead
-electromagnet radiation
-not attracted to charged plates
-must be accompanied by alpha or beta
Waves have 4 categories…what are they?
frequency, wave length, speed, and amplitude
what is frequency
number of waves that pass a point per second
-in s to the -1
Wave length
from crest to crest or trough to trough
-in nm
c=3* 10^8 m/s
height from origin to crest or trough
equations to know
c=?? or 3e8=??
Electromagnetic spectrum
it encompasses all forms of em radiation
minimum amount of energy gained or lost by atom
energy and frequency are…related
wavelength and frequency are…related
tiny bundle of energy
atomic emmision spectrum
set of frequencies emitted by atoms of an element (color patterns)
What was De Broglie’s question that he wanted to find out
if a wave can be a particle, can a particle be a wave?
heisenberg uncertainty principle
it is fundamentally impossible to find the velocity and position of an electron at the same time
quantum numbers explain 4things, what are they?
energy level electrons are on, the sublevel, direction it spins(clockwise+, counter-), and if its on a x, y, or z plane
l is the energy sublevel. it has 4 pts which are…
s= a circle, 1
p= figure 8, 3
d= clover, 5
f= 3D, 7
What is electron configuration
arrangement of electrons in an atom
Aufbau principal
each electron occupies the lowest energy orbital available
pauli exclusion principle
now 2 electrons have same set of 4 quantum numbers
hunds rule
longest definition btw
single electron with same spin must occupy each equal energy orbital for additional electron with opposite spin can occupy same orbital
Noble gas
perfection-dont bond-unreactive
noble gas configuration
short version
take noble gas that comes before the element
orbital diagram
uses the boxes
valance electrons
electrons in outer most orbital
max number is 8, only s and p count
shown as ve
2 elements w/ exceptions
chromium and copper

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