Chemistry Chapter 4 & 5

Greek Philosopher who named the smallest piece of matter (atom)

• Democritus

• Rutherford

• Hund

• Aufbau

Atoms are indestructible and indivisible*

Atoms of the same element are exactly alike*

Atoms can physically mix/can chemically combine in whole # ratios to form compounds

Chemical reactions = atoms join, separate, or rearrange

atoms of one element are never changed to atoms of a different element

• Rutherford's Gold Foil Experiment

• John Dalton's Atomic Theory

• Hund's Rule

• Pauli Exclusion Principle

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Discovered by J.J. Thomson (Plum Pudding Model)

Negatively charges subatomic particle

Mass = 1/1840th of a proton

• Neutron

• Proton

• Atom

• Electron

Discovered by Goldstein

Positively charged

1840x bigger than an electron

• Proton

• Atom

• Electron

• Neutron

Proposed that an atom is mostly empty space

All positive charges are concentrated in a small region

Nucleus is the central core made of protons and neutrons

• Democritus

• Rutherford

• Hund

• Pauli

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Nucleus

• Electrons and Protons

• Electrons and Neutrons

• Neutrons and Protons

• Atoms and Protons

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Atoms are identified by:

• Mass #

• # of Neutrons

• # of Protons

• Atomic Mass Unit

Atomic # (Found above the chemical symbol):

• # of Protons

• # of Neutrons

• Mass #

• Atomic Mass Unit

Mass #

• Total # of Protons and Electrons

• Total Mass # and Protons

• Total # of Protons and Neutrons

• Mass # - Atomic #

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# of Neutrons

• Mass # - Atomic #

• Atomic # - Mass #

• Protons - Electrons

• Protons - Neutrons

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