PROPERTIES OF IONIC COMPOUNDS

IONIC COMPOUND l ONE WITH IONIC BONDS l Ex: NaCl CuSO 4

OBJECTIVE After completing this presentation you should be able to: l List and explain 4 properties of ionic compounds l List several people who care about each property and explain why they care

1) FORM CRYSTALS l CRYSTAL: A REGULAR GEOMETRIC PATTERN

WHO CARES? l A) GEOLOGISTS l B) GEMOLOGISTS l * COMPUTER CHIP DESIGNERS

WHY FORM CRYSTALS? l IONS WANT CLOSEST PACKING POSSIBLE l A PATTERN FORMS (THE PATTERN DEPENDS ON THE SIZE OF THE IONS)

2) HIGH MELTING POINT l TEMPERATURE REQUIRED TO CHANGE THE SOLID TO LIQUID AVERAGES 1000  C

WHO CARES? l MATERIALS SCIENTISTS l SPECIALTY CERAMICS l PEOPLE WHO NEED HIGH MELTING POINT MATERIALS!!!

WHY HIGH MELTING POINT? l THE ELECTROSTATIC FORCE IS VERY STRONG l IT TAKES A LOT OF ENERGY TO BREAK THE FORCE TO ALLOW THE CRYSTAL TO MELT

3) DISSOLVE IN WATER l THEY’RE WATER SOLUBLE

WHO CARES? l FARMERS l MEDICAL PROFESSIONALS l ATHLETES

WHY WATER SOLUBLE? l WATER IS POLAR l THE IONS IN THE CRYSTAL ARE AS ATTRACTED TO THE WATER’S CHARGES AS TO OTHER IONS l THERE IS MORE WATER AND THE WATER MOVES MORE

4) THEY ARE ELECTROLYTES l ELECTROLYTE: CONDUCT ELECTRICITY WHEN DISSOLVED (OR MOLTEN)

WHO CARES? l MEDICAL PROFESSIONALS l ANYONE WHO WANTS TO BE HEALTHY

ELECTROLYTES Na + : important to many systems K + : respiratory system Ca +2 & Mg +2 : large muscle groups Others include: Zn +2, Li +, I -

WHY ARE THEY ELECTROLYTES? l IONS WILL CONDUCT ELECTRICITY WHEN THEY CAN MOVE l WHEN DISSOLVED THEY ARE FREE TO MOVE AND CARRY THE ELECTRICAL CURRENT l WHEN SOLID THEY CAN’T MOVE THEREFORE THEY DON’T CONDUCT