Download 4.1 – 4.2 Development of Atomic Theory

4.1 – 4.2 Development of Atomic Theory
For Each Scientist / Group:
1. Name the scientific discovery
2. Name the Accepted Model at the time
3. Name the year of discovery
4. Draw the most currently accepted model
Democritus
1_Coined term “atom”___________________
2_Atomic Model_________________________
3_460 – 370 B.C.________________________
Atoms are:
*Indivisible
*Smallest particle of a substance that
still retains the properties of the
substance.
*Like to all atoms of same element but
Different than atoms from another
Element.
Thompson
1_ electron_e-_________________________
2__Plum(b) Pudding Model_______________
3__1897________________________________
Used CRT to discover electrons.
Imagined them stuck like “plums in
plum pudding.”
http://www.youtube.com/watch?v=YTAC
1wMrVPk&feature=relmfu
Dalton
1_Laws of Definite and Multiple Proportions_
2_Dalton’s Atomic Theory________________
3_1803_________________________________
Name_______________________________
Date_____________________Hour______
Goldstein
Used CRT / canal rays to determine
atoms had “positiveness” in them.
Later, that positiveness was named
the proton.
Used / incorporated ALL of Democritus’ Theory
Added:
*Atoms cannot be created nor destroyed
*Atoms combine in simple wholenumber ratios to form compounds
*Work supported Law of Cons. Of Mass
Millikan
(Same Model!)
1_Mass (and charge) of an electron_________
2_Plum(b) Pudding Model________________
3__1909________________________________
Used the Oil Drop Experiment to
determine that the mass of an electron
is 1/1837 the mass of a proton;
charge = - 1
https://www.youtube.com/watch?v=X
MfYHag7Liw (1:13)
1__”positiveness” in an atom______________
2__Revised atom________________________
3__1886________________________________
https://www.youtube.com/watch?v=VdoTVk4
BFmk
Rutherford
1__Nucleus_____________________________
2__Nuclear Model_______________________
3__1911________________________________
Used the Gold Foil Experiment to
determine that the nucleus was
*very tiny
*centralized
*positively charged
*comprised most of the mass
https://www.youtube.com/watch?v
=zUtIrO3fUgg (start @ 1:22)
https://www.youtube.com/watch?v=GzMh4q-2HjM CRT Tube
This is a picture of “real” plumb pudding!
https://www.withfriendship.com/images/i/40036/card-33-of-56.gif
(Like positive dough and negative plums.)
(Same Model!)
Bohr
1__orbitals / electron paths________________
2__Orbital Model_(planetary)_____________
3__1913________________________________
*Electrons travel around the nucleus on
fixed paths or orbits.
*Each orbital / set of orbitals is within
a fixed energy level
*Student of Rutherford’s
Chadwick
1_Neutron____________________________
2_Revised Orbital Model________________
3_1932_______________________________
Used alpha particles to discover that the
neutron is:
*centrally located
*neutral in charge (no charge)
https://www.youtube.com/watch?v=ZK-yeuu_p9k (Start at 3:00)
Modern Day
1Electron Cloud / Probability Cloud Model
(Schrödinger*) 2_electron clouds / probability clouds_____
3_(1926) 1950’s_______________________
*Electrons reside in regions / clouds
(not on set paths)
*Shape of the cloud depends on the
type
*90% likelihood of finding electrons
within those clouds
https://www.youtube.com/watch?v=f64EYPIily4