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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.
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Electron Theory • Introduction • Structure and Matter • Atoms and Molecules • Atomic Structure • Electron Flow
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.
Structure and Matter • Matter • Can be solid, liquid or gas • Ice • Water • Air
Structure and Matter • Matter • Can be solid, liquid or gas • Can be element, compound, or mixture
Structure and Matter • Matter • Can be solid, liquid or gas • Can 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 • Matter • Can be solid, liquid or gas • Can 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 • Matter • Can be solid, liquid or gas • Can 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
Electrons Nucleus contains Protons & neutrons Atoms and Molecules • Atom- Smallest part of an element that retains the properties of that element • Electrons • Neutrons • Protons
Electrons Nucleus contains Protons & neutrons Atoms and Molecules • Atom • Electrons • Negative charge (-) • Neutrons • Protons
Electrons Nucleus contains Protons & neutrons Atoms and Molecules • Atom • Electrons • Neutrons • Neutral charge • within the nucleus • Protons
Electrons Nucleus contains Protons & neutrons Atoms and Molecules • Atom • Electrons • Neutrons • Protons • Positive charge • Within nucleus
Atoms • Have a Nucleus • Protons (positive charge) • Neutrons (neutral charge) • Orbiting electrons (negative charge)
Bohr Model (Hydrogen) Electron Nucleus (1 proton 1 neutron) N=1 H
Bohr Model (Helium) Electron Nucleus (2 protons 2 neutrons) Electron N=1 He
Bohr Model (Lithium) 1 valence electron Nucleus (3 protons 4 neutrons) N=1 N=2 Li
Bohr Model The number of electrons in each shell is determined by the formula: #electrons=2n2
Bohr Model (Copper) 1 valence electron N=1=2(1)2=2 N=2=2(2)2=8 N=3=2(3)2=18 N=4=2(4)2=32 Nucleus (29 protons 35 neutrons) 60 N=1 N=2 N=3 N=4 Cu
Cu 29 Copper 63.54 Copper Element
Cu 29 Copper 63.54 Copper Element Name
Cu 29 Copper 63.54 Copper Element Atomic Number Name
Cu 29 Copper 63.54 Copper Element Atomic Number Chemical Symbol Name
Cu 29 Copper 63.54 Copper Element Atomic Number Chemical Symbol Name 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. Light, Heat, or EMF Cu
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
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? Practice Problem: Solution: (6.24x1018)x.05 = 3.17x1017 electrons/second