Bonding, Structure And Properties Flashcards
WHAT ARE THE TYPICAL PROPETRTIES OF A METAL?
• Strong
•High melting point
• Good electrical conductivity
• Malleable
• Ductile
• Insoluble
• Shiny
HOW DOES IONIC BONDING OCCUR?
The outer electrons of a metal are transferred to the outer electron shell of a non-metal
WHAT HOLDS METALS TOGETHER?
Strong electrostatic attraction between positive metal ions and negative electrons
WHY DOES IONIC BONDING OCCUR?
To complete their outer shells and become stable
HOW CAN WE SHOW IONIC BONDING?
Electron transfer diagrams
HOW DO COVALENT BONDS FORM?
Non-metal atoms share their outer electrons in order to complete their outer shell and become stable
WHAT IS A COVALENT BOND?
A shared pair of electrons
HOW DO WE SHOW COVALENT BONDS?
Dot-and-cross diagrams
WHAT ARE THE PROPERTIES OF A SIMPLE COVALENT STRUCTURE?
• Low melting and boiling points
• Poor conductors of electricity
• Variable solubility in water
HOW MANY OF THE CARBON ATOMS ARE COVALENTLY BONDED IN DIAMOND?
All 4
WHAT ARE THE PROPERTIES OF DIAMOND?
• Very high melting point - strong covalent bonds that need a lot of energy to break.
• Very hard to- due to covalent bonds
• Electrical insulator - diamond does not have any free electrons so not a conductor of electricity
HOW MANY OF THE CARBON ATOMS ARE COVALENTLY BONDED IN GRAPHITE?
Only 3 of the 4 present
WHAT ARE THE PROPERTIES OF GRAPHITE?
• Very high melting point - strong covalent bonds that require a lot of energy to break
• Soft and slippery to the touch - atoms within each layer are held together by strong covalent bonds but the layers themselves are held together by weak intermolecular forces. So layers of carbon can easily slide over each other when force is applied.
• Good conductor of electricity - Delocalised electrons between layers carry electrical energy
WHAT ARE THE USES OF CARBON FULLERINES?
• Drug delivery
• Lubricant
• Catalyst
WHAT IS THE MOST COMMON FULLERINE?
Buckminsterfullerne
WHAT ARE THE PROPERTIES OF NANOTUBES?
• Very strong
• Soft and slippery
• Very good conductor of electricity
WHAT ARE THE PROPERTIES OF GRAPHINE?
• Very strong (300x stronger than steel)
• Best conductor of electricity known
WHAT IS A SMART MATERIAL?
Has at least one property that changes reversibly when environment changes in a certain way.
WHAT ARE THERMOCHROMIC PIGMENTS AND WHAT ARE THEIR USES?
Materials that change colour when reaching a specific temperature.
Uses - colour changing mugs
Battery power indicators
Bath toys for children
WHAT ARE PHOTOCHROMIC PIGMENTS AND WHAT ARE THEIR USES?
Change colour with light intensity (ultraviolet light)
Uses- dyes in clothing + lenses in glasses that darken in sun
WHAT ARE SHAPE MEMORY POLYMERS AND WHAT ARE THEIR USES?
Plastics that return to original shape when heated
Uses - Car bumpers, medical sutures, helmets
WHAT ARE SHAPE MEMORY ALLOYS AND WHAT ARE THEIR USES?
Metal alloys that return to original shape when heated
Uses- deformable spectacle frames, surgical wires for joining bone fractures
WHAT ARE HYDROGELS AND WHAT ARE THEIR USES?
Polymers that can absorb up to 1000x their own volume of water
Uses- nappies, house plant compost
HOW BIG ARE NANOPARTICLES?
Between 1 - 100 nanometers (nm)
WHAT ARE THE USES OF NANOPARTICLES?
•Sun cream
• Cleaning products
WHAT ARE THE ISSUES THAT COULD COME FROM USING NANOPARTICLES?
• They’re small - could pass through our skin into bloodstream
• Tasted for safety but - long-term effects of nanoparticles on human health + environment unknown
