Transcript First to propose idea of atom

First to propose idea of atom
Democritus
Wrote out the first four point
atomic theory
Dalton
Found the eThomson
Experimented with cathode
ray tubes
Thomson and Goldstein
Thomson’s plum pudding
Found the electrical charge of
the e
Millikan
Did the oil drop experiment
Millikan
Did the gold foil experiment
Rutherford
Found the proton
Goldstein
Found the nucleus
Rutherford
Found the neutron
Chadwick
Atomic Theory Polka
• Dalton, Thomson, Rutherford and Bohr.
Schrödinger and Heisenberg, and many,
many more. Used their brains to venture
in the realm of inner space and found the
world of the atom was a weird and
wondrous place.
• Dalton did experiments and said, “I think
it’s clear, atoms are tiny indestructible
spheres.”
• Thomson worked with cathode rays and
said, “I disagree. A plum-pudding model
makes much more sense to me.” A new
chapter in atomic theory started to unfold.
• When Rutherford played around with
atoms made of gold. When a few of his
alpha particles came bounding back, he
hypothesized a nucleus had knocked them
off the track.
• Dalton, Thomson, Rutherford and Bohr.
Schrödinger and Heisenberg, and many,
many more. Used their brains to venture
in the realm of inner space and found the
world of the atom was a weird and
wondrous place.
• Bohr saw spectral lines for hydrogen and
said, “It seems to me.. Electrons move in
orbits with specific energies.”
electron
neutron
proton
• Heisenberg said, “Forget it, there’s no way
to know the orbit or a path, where the
electron’s gonna go.”
• Schrödinger used lots and lots of fancy
mathematics, and made a model of the
atom based on quantum mechanics. It
has orbitals and those are based on
probability. The atom is a fuzzy blob of
pure uncertainty.
• Dalton, Thomson, Rutherford and Bohr.
Schrödinger and Heisenberg, and many,
many more. Used their brains to venture
in the realm of inner space and found the
world of the atom was a weird and
wondrous place.
What do you know about
atom?
How Atoms Differ
Date:
Subatomic
Particles
 PROTONS
 NEUTRON




p+
In the nucleus
+1 charge
1 amu





ELECTRON
eIn electron cloud
-1 charge
1/
1840 amu




no
In the nucleus
No charge
1 amu
Atomic number
 Used to arrange elements in PT by
Mosley
 # of PROTONS
 # of ELECTRONS
IF an ATOM
Isotopes
 Atoms of the same element that differ in
the # of neutrons
Atomic Mass
 The weighted average of all isotopes.
 Always a decimal (unless a man-made
element)
Mass number
 Mass of an isotope
 Always a whole number – not on PT
 # of PROTONS + NEUTRONS
Nuclide
 Tells atomic # and mass # of an atom
23 Na
11
 Sodium-23 has ____ protons, ___ electrons
and ____ neutrons
Practice
32 S
16
28 Si
14
14 C
6
Ions
 Atoms with a charge
CATIONS
 Cations are pawsitive and are written
with a plus charge on the upper right.
 LOST an e-, have more protons; therefore
positive.
 Charge indicates the number of electrons
lost.
 Hint: cation has a t which looks like +
ANIONS
 Anions are negative and written with a
negative charge on the upper right.
 GAINED an e-, have more electrons;
therefore negative.
 Charge indicates number of electrons
gained.
36
17
Cl
 _____ protons _____ neutrons
_____ electrons
Practice
16 O-2
8
108 Ag+
47
80 Br 35
207 Pb+4
82