Chemistry : Topic 1

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Atom: building block of matter

Dalton: Cannon Ball

3-D / Spherical

Solid / Hard

Uniform

Indivisible

same are the same

different is different

Infinite amount of Matter

J.J. Thompson: Cathode Ray = ( - ) particles make up matter

electrons

Model was the Plum Pie Pudding

Rutherford: Gold Foil Experiment

Mostly Empty Space

Small dense positive core = nucleus

Bohr: Planetary Model

Heisenberg: Wave Mechanical Model

Electrons are both particles & waves

Sometimes known as the cloud based model

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Matter --> Atoms (smallest recognizable piece of matter) --> Subatomic Parts

Subatomic Parts

Name Charge Mass Location

Electron (neg) ( n/a) orbital

Proton (pos) (1 amu) nucleus

Neutron (n/a) (1 amu) nucleus

Calculating #'s

** Use Periodic Table **

---------------------------

-- Atomic Mass --

-- "X" --

-- --

--Atomic # --

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1. Round atomic mass to nearest whole #.

2. # of protons ALWAYS equals the atomic #.

3. * All atoms* are neutral

# protons = # of electrons

4. Protons + Neutrons = Atomic Mass

Isotopes : 2 samples of the same element with different mass #'s because of different # of neutrons.

Iso = same

Changes to # of Subatomic Parts

Protons: NEVER EVER EVER CHANGES

Electrons: Charges =IONS -> charged part due to the gain or loss of electrons

(+) lost electrons

(-) gained electrons

Neutrons: Isotopes - 2 atoms of the same element with different mass #'s because of different #'s of neutrons C