Structure of the Atom

1
Structure of the Atom

• PSC Ch. 3-2

2
The Atom

• Subatomic particles
• The nucleus
• The notation and the periodic table
• Isotopes and Ions
• Determining atomic mass

3
Subatomic Particles

• Electrons
• Discovered by J.J. Thompson
• Discovered how
• Cathode ray tubes-rays traveled from cathode to
  anode, bent by electric and/or magnetic field,
  caused paddle wheel to turn
• Vital Stats
• Mass 9 X 10-31 kg , 1/2000 mass of p, .00055u
• Charge -1, -1.30x10-19c,
• Location electron cloud / outside nucleus

4
Subatomic Particles

• Protons
• Discovered by J.J. Thompson
• Discovered how
• Modified cathode ray tube particles traveled from
  anode to cathode
• Vital Stats
• Mass 1.673 X 10-27 kg 2000x mass of e-, 1.007u
• Charge 1, 1.60x10-19c
• Location nucleus

5
Subatomic Particles

• Neutrons
• Discovered by James Chadwick
• Discovered how
• High energy beam unaffected by magnetic or
  electric fields
• Vital Stats
• Mass 1.675 X 10-27 kg (very similar to the
  proton)
• Charge 0, neutral
• Location in the nucleus

6
The Nucleus

• Discovered by Lord Ernest Rutherford
• Discovered how
• Gold foil experiment- charged particles shot at
  thin gold foil. Most went straight through, some
  deflected. Very few bounced straight back
• Small dense charged core in atom (atom is
  mostly empty space)
• Vital Stats
• charge
• Dense over 99 of the atoms mass
• 1/trillionth the volume of the atom

7
Graphic Organizer
8
Isotopes

• Sometimes atoms of the same elements have a
  different number of neutrons
• All elements have isotopes!
• And they exist in different abundances.

9
Ions (p. 161)

• Sometimes atoms will gain or lose electrons
• Too many negative charge
• Too few positive charge