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Electron Theory. Introduction Structure and Matter Atoms and Molecules Atomic Structure Electron Flow. Introduction. Structure and Matter. In this section we will discuss the concept of Matter. Structure and Matter. Matter Definition: Anything that occupies space and has mass. - PowerPoint PPT Presentation
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Electron Theory
Introduction Structure and Matter Atoms and Molecules Atomic Structure Electron Flow
Introduction
In this section we will discuss the concept
of Matter.
Structure and Matter
Matter
Definition: Anything that occupies space and has mass.
Structure and Matter
Structure and Matter
MatterCan be solid, liquid or gas
Ice Water Air
Structure and Matter
MatterCan be solid, liquid or gasCan be element, compound, or mixture
Structure and Matter
MatterCan be solid, liquid or gasCan be element, compound, or mixture
Element- Is the basic building block of nature Purest form of matter. Can not be divided into simpler
substances (see periodic table) Hydrogen Oxygen Carbon
Structure and Matter
MatterCan be solid, liquid or gasCan be element, compound, or mixture
Element- Is the basic building block of nature Compound- Two or more chemically combined
elements Contain the same proportion throughout
CO2
H2O
Structure and Matter
MatterCan be solid, liquid or gasCan be element, compound, or mixture
Element- Is the basic building block of nature Compound- Two or more chemically combined
elements Mixture- Two or more elements not chemically
combined, (proportion may vary). i.e. Saltwater, Sand and Gravel
Atoms and Molecules
Atom Molecule Molecular Compound Ionic Compound
Atoms and Molecules
Atom- Smallest part of an element that retains the properties of that elementElectronsNeutronsProtons
Electrons
Nucleus containsProtons & neutrons
Atoms and Molecules
AtomElectrons
Negative charge (-)
NeutronsProtons
Electrons
Nucleus containsProtons & neutrons
Atoms and Molecules
AtomElectronsNeutrons
Neutral charge within the nucleus
Protons
Electrons
Nucleus containsProtons & neutrons
Atoms and Molecules
AtomElectronsNeutronsProtons
Positive charge Within nucleus
Electrons
Nucleus containsProtons & neutrons
Atoms
Have a NucleusProtons (positive charge)Neutrons (neutral charge)
Orbiting electrons (negative charge)
Bohr Model (Hydrogen)
Electron
Nucleus (1 proton 1 neutron)
HN=1
Bohr Model (Helium)
Electron
Nucleus (2 protons 2 neutrons)
HeN=1 Electron
Bohr Model (Lithium)
1 valence electron
Nucleus (3 protons 4 neutrons)
Li
N=1
N=2
Bohr Model
The number of electrons in each shell is determined by the formula:
#electrons=2n2
Bohr Model (Copper)
1 valence electron
Nucleus (29 protons 35 neutrons)
Cu
N=1
N=2
N=3
N=4
N=1=2(1)2=2N=2=2(2)2=8N=3=2(3)2=18N=4=2(4)2=32
60
Copper Element
Cu29
63.54Copper
Copper Element
Name
Cu29
63.54Copper
Copper Element
Atomic Number
Name
Cu29
63.54Copper
Copper Element
Atomic Number
Name
Cu29
63.54Copper
ChemicalSymbol
Copper Element
Atomic Number
Name
Cu29
63.54Copper
ChemicalSymbol
Atomic Weight
Electrons charge
The charge of 1 electron = 1.602x10-19 Coulombs
Or 1 Coulomb = 6.24x1018 electrons
Electrons excitation
Electrons will stay in orbit as long as the bond is present between the electron and the protons
Cu
Electrons excitation
When energy is present enough to break the proton and electron’s bond, the electron will release from the atoms outer most (valence) shell.
Cu
Light,Heat,orEMF
Electrons excitation
Direction of electron flow is produced when positive forces are strong enough to pull electrons in a direction.
Cu Cu
+
Cu Cu
-
Electrons excitation
Recall 1 Coulomb = 6.24x1018 electrons
That’s a heck of a lot of electrons!!!!
6,240,000,000,000,000,000 to be exact!!!!
Electrons Flow
Current = The directional flow of electrons from a negative to positive
Electrons Flow
1 Amp = the amount of 1 coulomb of electrons (6.24x1018) crossing an area per second
6.24x1018 electrons/second
_ +
Electrons Flow
This is defined as Current Flow “I” through a conductor
6.24x1018 electrons/second
_ +
Electrons Flow
If we were to say that 2 Amps is flowing in the conductor the # of electrons is (6.24x1018) x 2 and so on…..
6.24x1018 electrons/second
_ +
Electrons Flow
In an ideal world, current flow (electron movement) through a conductor would not have any resistance.
6.24x1018 electrons/second
_ +
Electrons Flow
As we shall see later, this is not the case.
6.24x1018 electrons/second
_ +
Electrons Flow
Until then simply understand current flow is the movement of electrons through a conductive material
6.24x1018 electrons/second
_ +
Practice Problem:
If a copper wire has 50mA of current flowing through it, how many electrons are passing through a single cross-sectional area each second?
Practice Problem:
If a copper wire has 50mA of current flowing through it, how many electrons are passing through a single cross-sectional area each second?
Solution:
(6.24x1018)x.05 = 3.17x1017 electrons/second
End of Presentation
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