Download Structure of the Atom

Structure of the
Atom
UNIT 3.1
CHAPTER 3 SECTION 2
The Atom
Definition - the smallest particle of an element that
can exist alone or in combination with other atoms.
(Dalton’s) Atomic Theory
All matter is made of atoms.
All atoms of a given element are identical in mass
and properties
◦ But the atoms of one element differ from all other
elements
Rutherford’s Experiment
“The Gold Foil Experiment”
◦ Fired particles at a piece of solid gold foil
Rutherford Expected:
Rutherford’s Results:
Rutherford’s Experiment
Observation
◦ Most particles pass through
undeflected.
◦ Some particles bounced back.
Conclusion
◦ Most of atom is open space.
◦ Dense center with a positive charge
Atom Composition
Protons (p +)
◦ Found in the nucleus
◦ Have mass, 1
◦ Positively charged
Atom Composition
Electrons (e-)
◦ Found on the outside
◦ “No mass,” 0
◦ Negative charge
Atom Composition
Neutrons (n)
◦ Found in the nucleus
◦ Have mass = 1
◦ No charge
Vocabulary
Vocabulary Word
Atom
Proton
Electron
Neutron
Definition
Picture
Exit Ticket
On a separate piece of paper:
1. Describe Dalton’s Atomic Theory.
2. Describes Rutherford’s Experiment and conclusion.
3. Draw and label the three parts of an atom.