C2- Bonding, Structure and Properties and Matter Flashcards
(69 cards)
1
Q
When are ions made?
A
When electrons are transferred
2
Q
Can ions be made from a group of atoms?
A
Yes
3
Q
How does ionic binding work?
A
When a metal and a nonmetal react together , the metal atom loses electrons to form a positively charged ion and the nonmetal gains these electrons to form a negatively charged ion. These oppositely charged ions are strongly attracted to one another by electrostatic forces. This attraction is called an ionic bond
4
Q
What kind of structure do ionic compounds have?
A
Giant ionic lattice
5
Q
Do ionic compounds all have similar properties?
A
Yes
6
Q
Do ionic compounds have a low melting and boiling point?
A
High, due to many strong bonds
7
Q
What is covalent bonding?
A
When nonmetal atoms bond together, they share pairs of electrons to make covalent bonds
8
Q
What are the 6 examples of properties of simple molecular substances?
A
- Simple molecular structures
- Very strong covalent bonds
- Low melting and boiling points
- Gasses or liquids
- As molecules get bigger, the strength of intermolecular forces increases, si more energy is needed to break them, and the melting and boiling points increase
- Don’t conduct electricity
9
Q
What are polymers?
A
Long chains of repeating units
10
Q
What do lots of small units link to form?
A
A long molecule
11
Q
What do all the atoms in a polymer joined by?
A
Covenant bonds
12
Q
What is the formula for poly(ethene)
A
C2H4
13
Q
Are the inter molecular forces between polymer molecules larger or smaller than between simple covenant molecules?
A
Larger
14
Q
Is more energy required to break forces between polymer molecules or covenant molecules?
A
Polymer
15
Q
What state are polymer at room temperature?
A
Solid
16
Q
Are the polymer molecules weaker or stronger than inionic or giant molecular compounds?
A
Weaker
17
Q
Are giant covalent structures macromolecules?
A
Yes
18
Q
Do giant covalent structures very low or high melting point?
A
High
19
Q
In diamond how many atoms form with one atom?
A
4
20
Q
In graphite how many atoms form with one atom?
A
3
21
Q
What type of structure is diamond?
A
Giant covalent
22
Q
Does diamond conduct electricity?
A
No
23
Q
Why doesn’t diamond conduct electricity?
A
No free electrons or ions
24
Q
What is the substance formed by sheets of carbon?
A
Graphite
25
Are there covalent bonds between the layers in graphite?
No
26
Can graphite be used as a lubricant?
Yes
27
Is graphite's melting point high or low?
High
28
What is the difference between graphene and graphite?
Graphene is one layer of graphite
29
What are fullerenes?
Molecules of carbon shaped like closed tubes or hollow balls
30
Do nanotubes conduct?
Yes
31
metallic bonding involves_ electrons
Delocalised
32
What is the structure for metals?
Giant structure
33
What shell is delocalised with a metal
Outer
34
Are most metals malleable?
Yes
35
What are the three states of matter
- Solid
- Liquid
- Gas
36
What 3 things determines how strong the force of attraction is?
- Material
- Temperature
- Pressure
37
What does the amount of energy required to change state depend on?
How strong the forces between the particles are
38
What are the three categories for particles
- Coarse particles
- Fine particles
- Nanoparticles
39
Nanoparticles have a small surface area to volume ratio. True/False
False. Large
40
What is the equation for surface area to volume ratio?
Surface area to volume ratio=Surface area ÷ volume
41
What are five uses of nanoparticles
- Catalysts
- Deliver drugs
- Conduct electricity
- Anti bacterial properties
- Cosmetics
42
What is the issue of nanoparticles with health?
Long term effects aren't known
43
Are nanoparticles used in suncream?
Yes
44
What type of elements are able to form covalent bonds
Non-metals
45
Discuss the uses and limitations if dot and cross diagrams
Dot and cross diagrams are used to show:
○ Charge of the ions
○ The arrangement of electrons in the atom or ion
○ Empirical formula (correct ratio of ions)
○ Which of the electrons in an ion originally come from
Dot and cross diagrams do not
○ Show the structure of the compound
○ Correctly represent the size of the ions
46
In an ionic compound, the particles are held together by _ forces of attraction. Theses forces act _ which results in the particles bonding together to form_
The words to pick from are weak,strong, in all directions, in one particular direction, giant lattices, small molecules
○Strong
○ In all directions
○ Giant lattices
47
What subtances do ionic bonding
Metal & non-metal
48
What is ionic bonding?
Ionic bonding is the electrostatic attraction between positive and negative
ions.
It is a relatively strong attraction.
49
How are ionic compounds held together
● They are held together in a giant lattice.
● It’s a regular structure that extends in all directions in a
substance.
● Electrostatic attraction between positive and negative ions holds
the structure together
50
State properties of ionic substances
● High melting and boiling point (strong electrostatic forces between
oppositely charged ions)
● Do not conduct electricity when solid (ions in fixed positions).
● Conduct when molten or dissolved in water - ions are free to move.
51
Give 5 examples of positive ions and 5 examples
of negative ions (give names of negative anions).
What is important when working out a formula of
an ionic compound?
```
E.g. Positive: Na+
, Mg2+, Al3+, Ca2+, Rb+
,
E.g. Negative: Cl−
, Br−
, SO4
2−, NO3
−
, OH−
(chloride, bromide, sulfate, nitrate,
hydroxide).
Ionic compounds are electrically neutral, i.e. positive and negative charges
balance each other.
```
52
How are ionic compounds formed? Explain in
| terms of MgO case.
Reaction of a metal with a non-metal.
Electron transfer occurs - metal gives away its outer shell electrons to
non-metal.
Mg is in Group II, so has 2 available outer shell electrons.
O is in Group VI, so can accept 2 electrons to get a full outer shell
configuration.
Mg becomes Mg2+ and O becomes O2− (oxide).
53
What is a covalent bond?
Covalent bond is a shared pair of electrons between two atoms.
54
Describe the structure and properties of simple
| molecular covalent substances
- Do not conduct electricity (no ions)
- Small molecules
- Weak intermolecular forces, therefore:
- Low melting and boiling points
55
How do intermolecular forces change as the
| mass/size of the molecule increases
They increase. That causes melting/boiling points to increase as well (more
energy needed to overcome these forces).
56
What are polymers? What are thermosoftening polymers?
Polymers are very large molecules (>100s, 1000s of atoms) with atoms linked by
covalent bonds.
Thermosoftening polymers - special type of polymers; they melt/soften when
heated. There are no bonds between polymer chains. Strong intermolecular forces
ensure that the structure is solid at room temperature. These forces are overcome
with heating - polymer melts.
57
What are giant covalent substances? Give examples
- Solids, atoms covalently bonded together in a giant lattice.
- High melting/boiling points – strong covalent bonds.
- Mostly don’t conduct electricity (no delocalised e−
)
- Diamond, graphite, silicon dioxide.
58
Describe and explain the
| properties of allotropes of carbon.
Diamond
– four, strong covalent bonds for each carbon atom
– very hard (Strong bonds)
– very high melting point (strong bonds)
– does not conduct (no delocalised electrons)
Graphite
– three covalent bonds for each carbon atom
– layers of hexagonal rings
– high melting point
– layers free to slide as weak intermolecular forces
between layers; soft, can be used as a lubricant
– conduct thermal and electricity due to one delocalised
electron per each carbon atom
```
Fullerenes
– hollow shaped molecules
– based on hexagonal rings but may have
5/7-carbon rings
– C60 has spherical shape, simple
molecular structure (Buckminsterfullerene)
Nanotubes
– cylindrical fullerene with high length to
diameter ratio
- High tensile strength (strong bonds)
- Conductivity (deloc. electrons)
Graphene - a single layer of graphite.
```
59
What is metallic bonding?
Forces of attraction between delocalised electrons and nuclei of metal
ions.
60
Describe properties of metals
- High melting/boiling points (strong forces of attraction)
- Good conductors of heat and electricity (delocalised electrons)
- Malleable, soft (layers of atoms can slide over each other whilst maintaining
the attraction forces)
61
What are alloys? Why are they harder than pure
| metals?
Alloys:
- mixtures of metal with other elements, usually metals
- different sizes of atoms distorts the layers, so they can’t slide over each other,
therefore alloys are harder than pure metals
62
What are the limitations of
| the simple model?
There are no forces between spheres and atoms, molecules and ions are solid
spheres – this is not true
63
What does the amount of energy needed to
change state from solid to liquid or liquid to gas
depend on?
The strength of the forces between the particles of the substance. The
nature of the particles involved depends on the type of bonding and the
structure of the substance. The stronger the forces between the particles
the higher the melting point and boiling point of the substance
64
A pure substance will melt or boil at…?
A fixed temperature.
| A mixture will melt over a range of temperatures.
65
What are the three states of matter?
Solid, liquid and gas
66
What is nanoscience?
Science that studies particles that are 1 - 100nm in size
67
State the uses of nanoparticles
- Medicine (drug delivery systems)
- Electronics
- Deodorants
- Sun creams (better skin coverage and more effective protection
against cell damage)
68
What are fine and coarse particles?
- Fine particles (soot), 100-2500 nm diameter
- Coarse particles (dust), 2500-105
nm diameter
69
Why do nanoparticles have properties different from
| those for the same materials in bulk
High surface area to volume ratio
