Giant Structures Flashcards
What state are giant ionic structures at room temperature?
solid
Why are ionic bonds hard to break?
Because a lot of energy is needed to break the ionic bond due to the strong electrostatic forces
Why do some ionic substances dissolve in water?
Because water molecules can split up the lattice
What bond are atoms in a molecule held together by?
covalent bonds
How high is the attraction inbetween simple molecules?
low because the covalent bond only acts between the atom and the molecule
What is the melting point of simple molecules like?
Low because of the weak force of attraction
Why do molecules not carry electrical charges?
Because they have no overall charge
What are the forces inbetween molecules called?
intermolecular
How strong are intermolecular forces?
weak
What state is a molecule with very weak intermolecular forces?
gas at room temp
What size do molecules with weak intermolecular forces tend to be?
small
What are larger molecules with stronger intermolecular forces at room temperature?
liquid
What happens when atoms with several covalent bonds join together?
They form giant covalent structures
What else is a giant covalent structure known as?
A macromolecule
What happens to the atoms in giant covalent structures?
They join together
Why do giant covalent structures have high melting points?
Because it takes a lot of energy to break down the lattice
What is diamond?
A form of carbon
What is the structure of diamond like?
regular and 3D
How many carbon atoms are covalently bonded to one in a diamond
One carbon atom is covalently bonded to 4 others
What makes diamond hard and transparent?
one carbon atom being covalently bonded to 4 others
What has a similar structure to diamond?
Silicon dioxide (silica)
What is graphite?
A form of carbon
How many carbon atoms are covalently bonded to one in graphite?
three
What is the structure of graphite like?
flat and 2D layers of covalently bonded carbon atoms
Why can the 2D layers in graphite slide over one and other?
Because the layers aren’t covalently bonded to one and other
What makes graphite slippery and grey?
The fact that the layers can slide over one and other
Why can graphite conduct heat and electricity?
Because one electron from each carbon atom is delocalised
What are the intermolecular forces between the layers of graphite like?
Weak
What are fullerenes?
Large molecules formed from hexagonal rings of carbon atoms
How do the hexagonal rings of carbon atoms join in fullerenes?
They join together to form cage like shapes
Can fullerenes be nanosized?
Yes
Why are metals easy to shape?
Because their layers can slide over one and other without breaking
How are metal atoms arranged?
In layers
Why are alloys harder than pure metals?
Because the different sized atoms distort the layers
Why is it easy for metals to conduct?
Because it is easy and quick to transfer energy throughout the lattice
