CHAPTER 1 ATOMIC STRUCTURE BASIC ELECTRICITY CHAPTER 1 ATOMIC STRUCTURE

TERMS TO KNOW ALTERNATING CURRENT(AC) ATOM ATTRACTION CENTRIFUGAL FORCE CONDUCTORS DIRECT CURRENT (DC) ELECTRON ELECTRON ORBITS INSULATORS MATTER NEGATIVE NEUTRON NUCLEUS POSITIVE PROTON SEMICONDUCTORS VALENCE ELECTRONS

HISTORY OF ELECTRICITY GREEKS DISCOVERED 2500 YEARS AGO USED PRACTICALLY ABOUT 100 YEARS AMBER BECAME CHARGED WHEN RUBBED WITH OTHER MATERIALS: ATTRACTED THINGS LIKE LEAVES, FEATHERS, BITS OF CLOTH THE WORD ELECTRIC COMES FROM THE WORD “ELEKTRON”

LIST A: POSITIVE LIST B: NEGATIVE

STUDY OF ATOMS ATOM IS THE BUILDING BLOCK OF UNIVERSE ALL MATTER IS MADE FROM A COMBINATION OF ATOMS MATTER IS ANY SUBSTANCE THAT HAS MASS AND TAKES UP SPACE MATTER CAN EXIST IN THREE FORMS: SOLID, LIQUID, OR GAS ELEMENT: CAN’T BE DIVIDED INTO A SIMPLER SUBSTANCE

STUDY OF ATOMS THREE STATES OF WATER

THREE PARTS OF AN ATOM: 1.ELECTRON 2. PROTON 3.NEUTRON NUCLEUS: PROTON AND NEUTRON NOTICE THE CHARGES OF EACH PART

PROTON=POSITIVE CHARGE ELECTRON=NEGATIVE CHARGE

Opposite charges attract and like charges repel LAW OF CHARGES…. Opposite charges attract and like charges repel

VALENCE ELECTRONS OUTER SHELL OF ATOM IS KNOWN AS “VALENCE SHELL” ELECTRONS LOCATED IN OUTER SHELL ARE “VALENCE ELECTRONS” THE VALENCE SHELL CAN’T HOLD MORE THAN 8 ELECTRONS

COPPER: GOOD CONDUCTOR BECAUSE OF ONLY ONE VALENCE ELECTRON

CURRENT FLOW HAPPENS WHEN ELECTRONS MOVE FROM ATOM TO ATOM.

INSULATORS: HAVE 7 OR 8 ELECTRONS IN VALENCE SHELL SEMICONDUCTORS: HAVE 4 ELECRONS IN VALENCE SHELL

CONDUCTORS THEY HAVE ONLY 1 OR 2 VALENCE ELECTRONS: THEY GIVE UP THOSE ELECTRONS EASILY WITH LITTLE EFFORT THEY ALLOW CURRENT FLOW EASILY: LOW RESISTANCE!!!!!!

EXAMPLES OF GOOD CONDUCTORS SILVER: 1 VALENCE ELECTRON COPPER: 1 VALENCE ELECTRON GOLD: 1 VALENCE ELECTRON ALUMINUM: 3 VALENCE ELECTRON PLATINUM: 1 VALENCE ELECTRON

INSULATORS MATERIALS THAT HAVE 7 OR 8 VALENCE ELECTRONS RESIST FLOW OF ELECTRICITY ELECTRONS ARE HELD TIGHTLY AND ARE NOT GIVEN UP EASILY

EXAMPLES OF INSULATORS RUBBER PLASTIC GLASS WOOD

SEMICONDUCTORS MATERIALS THAT HAVE 4 VALENCE ELECTRONS ARE NEITHER GOOD FOR CONDUCTORS OR INSULATORS USED TO MAKE DIODES AND TRANSISTORS COMPUTORS ARE FULL OF SEMICONDUCTOR MATERIAL SILICON AND GERMANIUM MOST COMMON USED

METHODS OF PRODUCING ELECTRICITY MAGNETISM=GENERATOR CHEMICAL=BATTERY PRESSURE=PIEZO SENSORS HEAT=THERMOCOUPLES FRICTION=STATIC LIGHT=PHOTO ELECTRIC

REVIEW….. OPEN THE BOOKS TO SUMMARY AT END OF CHAPTER. DO THE REVIEW QUESTIONS IN CLASS.