What does an atom look like?
Scientist /Name
Democritus (pg 67)
Model of Atom
Model (Picture) with Description

Democritus was a philosopher in 400 B.C. (not a scientist) that stated :
Nature’s basic particle is called an ________________ meaning
___________________.
Dalton (pg 68-69)
Model of Atom
1808 The First Atomic Theory (experimented & concluded)
1. All matter is composed of extremely small particles called _______________.
2. Atoms of the same element are identical; whereas, different element’s atoms are
different from each other in _________, _________, & __________ ______________.
3. Atoms cannot be _________________, ____________, or ________________.
4. Atoms of different elements combine in whole-number ratios to form _____________
5. Chemical reactions are when atoms are _______________, _________________, or
_____________________.
Cathode ray
experiment:
(pg 72-73)




_____________ ________________ was passed through gases in a glass tube.
The current passed through going from the negative (– ) cathode to the positive (+)
_______________.
Hypothesis: The current (cathode rays) were _______________ away by a negative
charge.
Thomson in 1897 concluded that all cathode rays are composed of identical
_______________ charged particles, which were named ___________________.
Millikan (pg 73)
Thomson (pg 73)
Model of the Atom
Millikan in 1909 measured the _____________ of an ________________ through the oil
drop experiment.
 Called his model of the atom the _______________ ______________ model.

The ____________ ___________ were spread evenly throughout the ___________
___________ of the rest of the atom.

Similar to seeds in a ___________________ where the seeds are spread throughout.
( Seeds = electrons
Gold Foil Experiment
Performed in 1911 by:
flesh of fruit = positive mass)
Label the image below using figure 6 on pg 74
___________________
pg74



Alpha particles have a _______________ charge.
Alpha particles were expected to pass through atom with _____________
deflection, most did.
But instead a few alpha particles had actually been deflected back ______________
the source.
Rutherford’s
Model of Atom
Label the image using figure 7 on pg 75
 A small number of positive alpha particles were _________________ backwards proves
that the nucleus is tiny and positive.
 Most of the particles passed through _________________ proves the atom is mostly
empty space.
Conclusion to the Goldfoil Experiment:
 Each atom contains a ___________, dense, _____________ charged ______________
surrounded by electrons
Bohr’s (pg 102)
Model of Atom ( 1913)
 Electrons can circle the nucleus only in allowed ____________ or ________________.
 The electron is in its lowest energy when it is in ___________ closet to the __________.
 This electron orbit at the lowest energy state is separated from the ___________ by a
large empty space where the electron ___________ exist.
 The energy of the electron is ____________ when the electron orbits successively
Planetary Model
________________ away from the nucleus.
 The electron orbit is also called the atomic _____________ level.
Schrodinger’s
Quantum Mechanical
(pg 106)
Model of Atom

Schrodinger in 1926 concluded through math that electrons move in waves of specific
energy.

Electrons do _________ travel around nucleus in neat _________ (disproving Bohr).

Electrons exist in certain regions called ________________ (electron cloud).

____________ is a three-dimensional region around the ________ that indicates the
__________________ location of an electron.

Atomic _________ have different ___________ and sizes.
pg 108

draw an s orbital

draw a p orbital

draw a d orbital
Building Elements:
(http://tinyurl.com/ok7eao6)
Sketch Helium atom
(Your final answer)
1. Helium: atomic number: ____________
#p+ _________ #e- _________
a) Complete the orbital diagram for helium.
(What you see in the electrons box)
1s
2s
2px
2py
2pz
b) Write the electron configuration for helium. ___________________________
(do later)
Sketch Carbon atom
(Your final answer)
2. Carbon: atomic number: ____________
#p+ _________ #e- _________
a) Complete the orbital diagram for carbon.
(What you see in the electrons box)
1s
2s
2px
2py
2pz
b) Write the electron configuration for carbon. ___________________________
(do later)
Sketch Sodium atom
(Your final answer)
3 Sodium: atomic number: ____________
#p+ _________ #e- _________
a) Complete the orbital diagram for sodium.
(What you see in the electrons box)
1s
2s
2px
2py
2pz
3s
b) Write the electron configuration for sodium. ___________________________
(do later)
Conclusion: An orbital is the electron cloud _________________. Each orbital can only hold _______ electrons. Every
orbital has to be given _____ electron before one orbital shape can be given _____. The s orbital is a _________ that
can hold _____ electrons. The p orbital is a _______ that can hold a max of ____ electrons but it has ____ different
shapes , _______, _______, & _______on ____ different axis.
Nucleus: Contains
______________________________
1st Energy Level: Can hold a maximum of ______ electrons in one orbital.
2nd Energy Level: Can hold a maximum of ______ electrons
distributed over ______ different orbitals.
3rd Energy Level: Can hold a maximum of ______ electrons distributed over
______ different orbitals.
Heisenberg‘s Uncertainty Principal: ( pg 105)
It is impossible to know simultaneously both the ______________ and ______________ of an electron.