C3 - Structure and Bonding Flashcards
1
Q
Where do ionic bonds form?
A
- Compounds formed from metals + non-metals
- Oppositely charged ions
2
Q
What is ionic bonding?
A
- Metal donates electrons to a non-metal
- Metal loses electrons to form positive ion
- Non metal gains electrons to form negative ion and full outer shell
3
Q
What is an ionic compound?
A
- Giant structure of ions
- Held together by strong electrostatic forces of attraction between oppositely charged ions
4
Q
Describe the structure of a crystal of sodium chloride, 3 POINTS
A
- Giant ionic lattice
- The positive sodium and negative chlorine ions form a closely packed regular arrangement
- Very strong electrostatic forces of attraction between the oppositely charged ions
5
Q
What are the main properties of ionic compounds?
A
- High melting + boiling points - strong bonds between molecules
- No electricity conducted when solid - ions not able to move freely in fixed position
- Conduct electricity when molten/dissolved - ions free + able to move
6
Q
What is an ion?
A
- Number of protons different from number of electrons
7
Q
What is the ion for group 1?
A
+1
8
Q
What is the ion for group 2?
A
+2
9
Q
What is the ion for group 3?
A
+3
10
Q
What is the ion for group 5?
A
3-
11
Q
What is the ion for group 6?
A
2-
12
Q
What is the ion for group 7?
A
1-
13
Q
What is the ion for hydroxide?
A
OH-
14
Q
What is the ion for sulfate?
A
SO4(-2)
15
Q
What is the ion for nitrate?
A
NO3(1-)
16
Q
What is the ion for carbonate?
A
CO3(2-)
17
Q
What is the ion for ammonium?
A
NH4(+1)
18
Q
Where do covalent bonds form?
A
- In most non-metallic elements
- In compounds of non-metals
19
Q
What is covalent bonding?
A
- Electrons are shared between non-metal atoms
- Number of electrons depends on how many electrons an atom need to make full outer shell
20
Q
What are the 2 properites of small covalent molecules?
A
- Low melting + boiling points - weak bonds between molecules so little energy needed
- Poor conductors - no delocalised electrons/ions to carry charge
21
Q
What are giant covalent structures?
A
- Many billions of atoms, each with a strong covalent bond
22
Q
What are the properties and structure of diamond? (3)
A
- Each carbon atom covalently bonded to 4 others
- High melting + boiling points - strong covalent bonds between atoms which take lots of energy to overcome
23
Q
What is the structure and properties of graphite?(4)
A
- Giant covalent structure
- Each carbon atom bonded to 3 others in hexagonal rings in layers
- High melting + boiling points - strong bonds
- Can conduct electricity - free electrons
24
Q
What are the properties and structure of graphene?
A
- Single layer of graphite
- Conducts electricty
- Very strong
- Used in high tech
25
What are fullerenes?
- Molecules of carbon atoms with hollow shapes
26
What is the structure and uses of buckminsterfullerene? (4)
- 60 carbon atoms
- Weak, intermolecular forces
- Can slide over each other
- Used for lubricants or drug delivery
27
What is metallic bonding?
- The electrons in the outer shell of metal atoms are delocalised and so are free to move through the whole structure
- The sharing of delocalised electrons
28
Explain the properties of carbon nanotubes? (3)
- High tensile strength
- High melting point as each atom is joined covalently to 3 others
- Sea of delocalised electrons, free to move - electricity conducted
29
What are the problems with the simple particle model? (3)
- No forces shown
- Assumes they are all spheres
- Assumes they are all solid
30
How are atoms arranged in pure metals?
- atoms are arranged in layers, which allows metals to be bent and shaped
31
How and why are alloys made?
- Mix multiple pure metals as they are too soft for many uses
- Alloys are harder
32
Why are alloys harder than pure metals?
- Alloys contain atoms of different sizes, which distort the regular arrangements of atoms
- Harder to slide over each other
33
What is nanoscience?
The study of structures that are between 1 and 100 nanometres (nm) in size
34
Why are properties of nanoparticulate materials different to same material in bulk?
- the tiny size of nanoparticles compared to the same material in bulk
- the large surface area to volume ratios of nanoparticulate materials compared to the same material in bulk
35
What are the uses of nanoparticles?
- Suncream, deodorant
- Electronics
- Catalysts
36
What are two risks of nanoparticles?
- Could catalyse harmful reactions in the body
- Organ damage
