Chemistry Topic 2
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/43
There's no tags or description
Looks like no tags are added yet.
44 Terms
What is one major flaw with the simple sphere model of matter?
It ignores the forces between the particles.
Why do some substances have very high melting points?
They have strong forces holding the particles together that need a lot of energy to break.
What type of bond forms between a metal and a non
metal?
What happens to electrons in ionic bonding?
Metals lose electrons and non
What type of charge does a metal ion get?
Positive.
What type of charge does a non
metal ion get?
What force holds an ionic bond together?
Electrostatic attraction between opposite charges.
What giant structure do ionic compounds form?
A giant ionic lattice.
Do ionic compounds have high or low melting points?
High melting points because the electrostatic forces are very strong.
Can solid ionic compounds conduct electricity?
No, because the ions cannot move.
When can ionic compounds conduct electricity?
When they are melted (molten) or dissolved in water, because the ions can move.
What type of bond forms between two non
metals?
What happens to electrons in a covalent bond?
A pair of electrons is shared between atoms.
What actually breaks when a simple molecular substance melts?
The weak intermolecular forces between the molecules.
Why do simple molecules have low melting points?
The forces between the separate molecules are very weak.
Do simple molecules conduct electricity?
No, because they do not have any free electrons or overall charge.
How does the size of a molecule affect its intermolecular forces?
Bigger molecules have stronger forces between them.
What holds the atoms together in a long polymer chain?
Strong covalent bonds.
What type of structure do Diamond and Silicon Dioxide have?
Giant covalent structures.
How many covalent bonds does each carbon atom form in Diamond?
4 bonds.
Why is Diamond so incredibly hard?
Every carbon atom is locked in place by 4 strong covalent bonds.
Does Diamond conduct electricity?
No, because it has no free electrons.
How many covalent bonds does each carbon atom form in Graphite?
3 bonds.
How are the atoms arranged in Graphite?
In flat layers of hexagons.
Why is graphite soft and slippery enough to be a lubricant?
There are weak forces between the layers, so they can slide over each other.
Why can graphite conduct electricity and heat?
It has delocalised electrons that are free to move through the structure.
What is graphene?
A single, one
What are fullerenes?
Hollow cages or tubes made entirely of carbon atoms.
What was the first fullerene ever discovered?
Buckminsterfullerene (C60).
What is a carbon nanotube?
A long, cylindrical fullerene tube.
What are two great properties of carbon nanotubes?
They are very strong and conduct electricity well.
What type of bond is found inside metals?
A metallic bond.
How is the structure of a metal described?
A regular grid of positive metal ions surrounded by a "sea" of free (delocalised) electrons.
Why do metals conduct electricity and heat so well?
The free electrons can move through the whole structure carrying charge and energy.
Why can pure metals be easily bent and hammered into shape?
The atoms are in neat layers that can slide past each other.
What is an alloy?
A mixture of a metal with another element.
Why are alloys harder than pure metals?
The different
How big are nanoparticles?
Between 1 and 100 nanometers wide.
What is the main structural feature of nanoparticles?
They have a very high surface area to volume ratio.
Why is a high surface area to volume ratio useful?
You only need a tiny amount of the material for it to work effectively.
Give two uses of nanoparticles?
Sunscreens, medicines, electronics, or catalysts.
How big are coarse particles (like dust)?
Between 2,500 and 10,000 nanometers.
How big are fine particles?
Between 100 and 2,500 nanometers.
What is a worry about using nanoparticles in medicine?
They might get inside our cells or lungs and cause unknown long