Download Unit 1 Atomic Structure

Unit 1 Atomic Structure
History
The Greeks were the first to discover
electricity 2500 years ago. The Greeks
called amber elektron.
About 300 years ago Charles DuFay
studied the force of repulsion and
attraction using a glass rod.
Unit 1 Atomic Structure
List of charged materials.
Unit 1 Atomic Structure
Unlike charges attract and like charges repel.
Unit 1 Atomic Structure
Atoms
• The atom is the basic building block of the
universe.
• An element is a substance that cannot be
chemically divided into a simpler substance.
• The principal parts of an atom are the
electron, neutron, and proton.
Unit 1 Atomic Structure
Atomic Theory
• An element is composed of only one type of
atom.
• The atomic number of an element is the same
as the number of protons in the nucleus.
• The Periodic Table of Elements lists all the
types of atoms or elements known to mankind.
• A molecule is the result of the joining of two or
more different types of atoms.
Unit 1 Atomic Structure
Water can exist in three states.
Table of elements.
Unit 1 Atomic Structure
The three principal parts of an atom are the
electron, the neutron, and the proton.
Unit 1 Atomic Structure
• The electron has a
negative charge and
orbits the nucleus.
• Protons have a positive
charge.
• Neutrons have no charge
and combine with the
protons to form the
nucleus.
Unit 1 Atomic Structure
Protons have a positive
charge.
Electrons have a
negative charge.
Unit 1 Atomic Structure
The Law of Charges
Opposite charges attract!
Unit 1 Atomic Structure
The Law of Charges
Like charges repel.
Unit 1 Atomic Structure
Bohr’s model of the
atom proposed that
electrons orbit the
nucleus in much the
same way that
planets orbit the sun.
Unit 1 Atomic Structure
Electrons form orbits or shells that surround the
nucleus.
Unit 1 Atomic Structure
Electrons orbit the nucleus in a circular fashion.
Unit 1 Atomic Structure
Valence electrons are located in the outer orbit of
an atom.
Unit 1 Atomic Structure
A copper atom contains 29 electrons and has one
valence electron.
Unit 1 Atomic Structure
Electron Flow
• Electricity is the flow of electrons.
• This happens when a free electron knocks
another electron free out of its orbit.
• The striking electron settles into a new
orbit.
• This process repeated many times creates
electrical flow.
Unit 1 Atomic Structure
An electron of one atom knocks an electron of
another atom out of orbit and takes its place.
Unit 1 Atomic Structure
The energy of the cue ball is transferred to the ball
being struck.
Unit 1 Atomic Structure
The energy of the striking electron is divided.
Unit 1 Atomic Structure
The energy of the cue ball is divided between the
other two balls.
Unit 1 Atomic Structure
The energy of the striking electron is divided among
the eight electrons.
Unit 1 Atomic Structure
Semiconductors
• Semiconductors are materials that are
neither good conductors nor good
insulators.
• They contain four valence electrons.
• When heated, their resistance decreases.
• Two common materials are silicon and
germanium.
Unit 1 Atomic Structure
Semiconductors contain four valence electrons.
Unit 1 Atomic Structure
Molecules are formed when atoms are joined
together.
Unit 1 Atomic Structure
There are six basic methods for producing
electricity:
1. magnetism
2. chemical action
3. pressure
4. heat
5. friction
6. light
Unit 1 Atomic Structure
There are five basic effects electricity can
cause:
1. magnetism
2. chemical reactions
3. pressure
4. heat
5. light
Unit 1 Atomic Structure
Producing sound with electricity.
Unit 1 Atomic Structure
Insulators
• Insulators resist the flow of electricity.
• They contain seven or eight valence
electrons.
• Examples of insulators are: rubber, plastic,
glass, and wood.