Topic 2- Bonding Flashcards
what does the term delocalised electron mean?
a free electron
what is an isotope?
Different forms of the same element that have the same number of protons but a different number of neutrons
Why is something a gas at room temperature??
- Made up of small molecules
- Weak intermolecular force
- Don’t require much energy to separate them
How to tell what has the lowest boiling point?
It has a smaller atom it has a lower boiling point
Can a metal be a gas at room temperature?
No
Why in group 7 is the reactivity the other way round?
It only need to gain one electron
Because the atom is so small the electrons are close to the nucleus as it has fewer shells so the intermolecular force is stronger so it is easier to attract 1 electron so little energy is needed.
the reaction is reactive as you go down the group there are more shells increasing the distance between the nucleus is greater which means electrons aren’t attracted
Why is group 1 more reactive at the bottom
Because the distance is longer meaning the intermolecular force isn’t strong which means little energy is needed to loose the electron so the electron gets lost easily making it more reactive because as you go down the periodic table the number of shells increases decreasing the intermolecular force between the outer electron weak
why is so and so a gas
The structure and properties of diamond
structure:
•4 covalent bonds between carbon atoms
Properties:
•Hard - 4 strong covalent bonds hold atoms rigidly in place.
•Does not conduct electricity- no free(delocalised) electrons to carry a charge
•High melting point- strong covalent bonds between atoms that need a lot of energy to overcome
what is the structure and properties of graphite
Structure:
•3 strong covalent bonds between carbon atoms
•Free(delocalised) electron
Made of layers that easily slide over each other
•The carbon atoms form layers of hexagonal rings
•There are no covalent bonds between the layers
Properties:
•Soft- formed from layers that easily slide over each other
•Conducts electricity- has a free(delocalised) electron to carry a charge
what are the uses for Dimond?
•Cutting tools as it is hard because it has 4 strong covalent bonds between the carbon atoms
e.g. diamond tipped glass cutters and oil rig drills
What are the uses for graphite?
electrodes in batteries and in for electrolysis as it can conduct electricity because it has a delocalised electron
what are fullerenes?
- A form of carbon
* Molecules of carbon with hollow shapes. Their structures are based on hexagonal rings of carbon atoms.
what is a nanotube?
Long cylindrical molecules made from carbon atoms joined together by covalent bonds.
what is a buckyball?
Molecules comprising carbon atoms joined together to form spherical or nearly spherical hollow structures.
nanotubes properties
- high tensile strength(can withstand a lot of tension)
- strong
- Conduct electricity- delocalised electron
List buckyballs properties
- weak intermolecular force exist between individual buckyballs
- Low melting point-little energy is needed to overcome these forces
- slippery and weak
how many carbon atoms does buckminsterfullerene have?
Buckminsterfullerene, C60, has sixty carbon atoms joined by covalent bonds
when are covalent bonds formed?
when two non metal atoms share pairs of electrons
Why are covalent bonds strong?
because the shared electrons are attracted to the nucleus of both atoms
What are metallic bonds?
Metallic bonds are the electrostatic attractions between positive ions and negative delocalised electrons.
What do we call the bonds that form when non-metal atoms share pairs of electrons?
covalent bonding
List the properties of metallic bonds
- Good conductors-delocalised electrons to carry a charge
- Malleable- can be hammered into sheets
- Ductile- Can be drawn into rods and wires
Why are metals ductile and malleable?
Because the ions easily move over each other.
