Bonding, structure and properties of matter Flashcards
What are the three states of matter?
Solid, liquid and gas
What affects how strong the forces of a material are?
The material, the temperature and the pressure
What direction do the particles in gases move in?
Straight lines
What do physical changes affect in particles?
Their arrangement or energy, not the particles themselves
How does a solid melt in terms of particles?
When a solid is heated, the particles gain more energy and vibrate which weakens the forces that hold the solid together. At the melting point, the particles have enough energy to break free from their position.
What happens when a gas condenses?
The particles no longer have enough energy to overcome the forces of attraction between them, so become a liquid
What form of bonding involves a non-metal and a metal?
Ionic bonding
What form of bonding involves a non-metal and a non-metal?
Covalent bonding
What form of bonding involves a metal?
Metallic bonding
What is an ionic bond?
The attraction of electrostatic forces between a positively charged metal ion and a negatively charged non-metal ion after transferring electrons
What structure do ionic compounds have?
A regular lattice structure, or a giant ionic lattice
What are the main properties of ionic compounds?
High melting and boiling points and can conduct electricity when melted or in a solution and
Are covalent bonds strong or weak and why?
Strong because the positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces
What are simple molecular substances?
Molecules containing a few atoms joined together by covalent bonds
Finish this sentence: the forces of attraction between simple covalent molecules are very
Weak
Finish this sentence: to melt or boil a simple covalent molecule, you have to
Break the feeble intermolecular forces and NOT the strong covalent bonds
What state are most simple molecular substances at room temperature and why?
Gas because they have very low boiling points
Finish this sentence: as molecules get bigger, the strength of intermolecular forces
Increases, so more energy is needed to break them which means that the melting and boiling points are higher
Do simple molecular compounds conduct electricity and why?
No because they aren’t charged, so there aren’t any free electrons or ions to carry the current
What is a polymer?
Lots of small units linked together to form a long molecule that has repeating sections
Do polymers have smaller or larger intermolecular forces and how does this affect their properties?
Larger so more energy is needed to break them which means that they are normally solids at room temperature
What are the properties of giant covalent bonds and why?
They have high melting and boiling points as lots of energy is needed to break the covalent bonds and cannot conduct electricity, even when molten as their are no charged particles
Why can graphite conduct electricity?
Each carbon atom has one delocalised electron
What are fullerenes?
They are molecules of carbon that are shaped like closed tubes or hollow balls
What can fullerenes be used for?
Caging other molecules (could be used to deliver a drug into the body), industrial catalysts ans lubricants
What are nanotubes?
Tiny carbon cylinders
What are the properties of nanotubes?
They can conduct both electricity and thermal energy and have a high tensile strength (they don’t break when stretched)
What can nanotubes be used for?
Electronics or strengthening materials without adding much weight
What are the properties of metals and why?
They have a high melting and boiling point because the sea of delocalised electrons and metal atoms have strong electrostatic forces, they are good conductors as the delocalised electrons can carry charge and are very malleable as the layers of particles can easily slide over each other
What is the equation for surface area to volume ratio?
surface area / volume
Finish this sentence: as particles decrease in size
Their surface area to volume ratio expands
