Today: Review (and a couple other things) (Important info… you must memorize start and stop codons.)
Ap CHemistry Chapter Two Atoms & Elements Please do not memorize dates--I will never ask you for an...
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Transcript of Ap CHemistry Chapter Two Atoms & Elements Please do not memorize dates--I will never ask you for an...
Ap CHemistryAp CHemistryChapter TwoChapter Two
Atoms & ElementsAtoms & Elements
Please do not memorize dates--I will never ask you for an exact one.However, you should have an idea (century-wise) of when
events/discoveries happened.
Ben FranklinBen Franklin1706-1790Two types charge
Positive & negative
Charges balance
If there is a positive charge,
somewhere there is a negative charge of equal magnitude
Still didn’t know about electrons
But had electricity
Henri BecquerelHenri Becquerel 1852-1908 1852-1908
Uranium on photographic plates
Emitted Rays
Pals with Marie Curie
She called it radioactivity
Marie Curie
Isolated polonium and radium
Cathode Ray TubeJ. J. Thompson
Evacuated glass tube
Metal electrodes
electric current produced glowing beamBent by magnetic field
ElectronsPlease to go the following link:
http://www.youtube.com/watch?v=IdTxGJjA4Jw
There are more slides
Ernest Rutherford
Nucleus small, dense
Gold Foil Experiment1909
Positive charge
Atom mostly empty space
Please go to this web page, but there are more slides after this one
http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf
Robert Milliken1868-1953
Measured charge on electronOil Drop Experiment
http://video.google.com/videosearch?hl=en&q=oil%20drop%20experiment&ie=UTF-8&sa=N&tab=iv#
Please follow this link
Like a perfume sprayer
Gives droplets a charge
James Chadwick 1891- 1974Neutron
Alpha particles hit beryllium
Beryllium released radiation
Radiation hit wax & caused protons to come off
Atomic Number & Mass
Cr24
51.99
Z= atomic numberalso = #protons
Atomic number gives atom its identity
Average massfrom isotopes
Mass from neutrons and protons
Relative mass
Look at atom’s mass in relation to the mass of carbon
The Mole
Latin: heap
1 mole = 6.022 x 1023
Li6.941
1 mole = 6.022 x 1023 atoms, ions, molecules
3Al13
26.98This many grams = 1 moleDifferent for each element
But
AlwaysDiatomic
H, N,O , and HalidesNeed to double massN
14.0 1 mole = 28.0 g
The Periodic LawMendeleevarranged by mass
Moseley
arranged by atomic masscurrently
http://videos.howstuffworks.com/hsw/5810-atomic-structure-periodic-law-video.htm
Please view the following 2 links
http://videos.howstuffworks.com/hsw/5811-atomic-structure-modern-periodic-table-video.htm
http://www.youtube.com/watch?v=JrK8mK_v1XY
Quiz yourselfQuiz yourselfExperimented with photographic plates& discovered radioactivityHenri Becquerel
Named Becquerel’s discovery radioactivityMarie Curie
Who discovered the electron & what experimentJ.J. Thompson, Cathode Ray
How did Thompson determine the electron was negativeBent in magnetic field
What scientist demonstrated the existence of the nucleus & what experiment
Rutherford, Gold foil
What else did Rutherford’s experiment show about the nucleussmall, dense, + charge, contributes the mass
Who measured the charge on the electron & what experimentMillikan, Oil drop
What is the atomic number of oxygen,how many electrons & protons8,8,8What is the mass of 1 mole of oxygen32.0 g It is diatomic
The mass of the elements are relative to what other element Carbon
What elements are diatomichydrogen, nitrogen, oxygen and the halidesWho is credited with the first periodic table &
how was it arranged?Mendeleev, by mass
Who changed Mendeleev’s arrangement, and how are the elements currently ordered?Moseley, by atomic number
100 %!!!