P1-Topic 2-Bonding, Structure, and The Properties of Matter

Question 1

What is ionic bonding? 3

Answer 1

Ionic bonding is the electrostatic attraction between positive and negative ions

metals,non- metals
It is a relatively strong attraction

Question 2

How are ionic compounds

held together? 3

Answer 2

They are held together in a giant lattice

a regular structure that extends in all directions in a substance.

Electrostatic attraction between positive and negative ions holds
the structure together

Question 3

State properties of ionic

substances 3

Answer 3

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

Question 4

What is important when working out a formula of

an ionic compound? 2

Answer 4

Ionic compounds are electrically neutral,

positive and negative charges balance each other.

Question 5

What is a covalent bond?

Answer 5

when atoms share one or more pairs of electrons

Question 6

Describe the structure and properties of simple molecular covalent substances 4

Answer 6

Do not conduct electricity (no ions)

• Small molecules
• Weak intermolecular forces
• Low melting and boiling points

Question 7

How do intermolecular forces change as the

mass/size of the molecule increases?

Answer 7

They increase.

That causes melting/boiling points to increase as well (more energy needed to overcome these forces).

Question 8

What are polymers?

Answer 8

Polymers are very large molecules (>100s, 1000s of atoms) with atoms linked by covalent bonds

Question 9

What are thermosoftening polymers? 2

Answer 9

they melt/soften when
heated

Strong intermolecular forces mean the structure is solid at room temperature.

Question 10

What are giant covalent substances? Give examples 4

Answer 10

Solids, atoms covalently bonded together in a giant lattice

• ## High melting/boiling points – strong covalent bonds.Mostly don’t conduct electricity- no delocalised electrons

Diamond, graphite, silicon dioxide.

Question 11

what are the limitations of using dot and cross
diagrams to represent molecules
or giant structures

Answer 11

.xdoesn’t show 3D arrangements of the atoms and electron shells

Doesn’t indicate the relative sizes of the atoms

Question 12

what are the limitations of using the ball and stick diagram 2

Answer 12

doesn’t show the movement of electrons

atoms placed far apart from each other as in reality the gaps between atoms are much smaller

Question 13

what are the limitations of using two dimensional diagrams to represent molecules
or giant structures 2

Answer 13

doesn’t show the relative sizes of the atoms and bonds

Cannot give you an idea of the shape of a molecule and what it looks like in 3D space

Question 14

what are the limitations of using three-dimensional diagrams to represent molecules
or giant structures 2

Answer 14

Only illustrate the outermost layer of the compound

Are difficult and time-consuming to draw

Question 15

What is metallic bonding?

Answer 15

Forces of attraction between delocalised electrons and nuclei of metal
ions.

Question 16

Describe properties of

metals 2

Answer 16

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)

Question 17

What are alloys? Why are
they harder than pure
metals?2

Answer 17

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

Question 18

What are the limitations of

the simple model? (particle theory) 3

Answer 18

no forces

that all particles are represented as spheres

that the spheres are
solid.

this is not true

Question 19

What does the amount of energy needed to change state from solid
to liquid or liquid to gas depend on? 3

Answer 19

strength of the forces between the particles of the substance

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

Question 20

A pure substance will melt or boil at…?

What about the
mixture?

Answer 20

A fixed temperature

A mixture will melt over a range of temperatures.

Question 21

explain the properties of diamond in terms of its structure and bonding. 4

Answer 21

four, strong covalent bonds for each carbon atom

– very hard (Strong bonds)

– very high melting point (strong bonds)

– does not conduct (no delocalised electrons)

Question 22

explain the properties of Graphite in terms of its structure and bonding 3

Answer 22

three covalent bonds with
three other carbon atoms,

layers of hexagonal rings

no covalent bonds between the layers

Question 23

How is graphite similar to metals 2

Answer 23

conduct thermal and electricity

one delocalised electron per each carbon atom

Question 24

explain the properties of graphene in terms of its structure and bonding. 2

Answer 24

a single layer of graphite

has properties that make
it useful in electronics and composites

Question 25

what is a fullrene

Answer 25

molecules of carbon atoms with hollow shapes

structure is hexagonal rings of carbon atoms-may have rings with 5or7 carbon atoms.

Question 26

what are carbon nanotubes

Answer 26

cylindrical fullerenes with very high length to diameter ratios.

useful for nanotechnology, electronics and materials

Question 27

uses of fullerenes, including carbon

nanotubes 2

Answer 27

lubricants, to deliver drugs in the body and
catalysts

reinforcing materials, tennis rackets

Question 28

What is nanoscience?

Answer 28

Science that studies particles that are 1 - 100nm in size

Question 29

State the uses of nanoparticles 4

Answer 29

Medicine (drug delivery systems)

• Electronics
• Deodorants
• Sun creams (better skin coverage and more effective protection
  against cell damage

Question 30

explain that there are possible risks associated with the use of
nanoparticles 3

Answer 30

may be toxic to people.

may be able to enter the brain from the bloodstream and cause harm

Once inside the body, they might catalyse reactions that are harmful.

Question 31

What are fine and coarse

particles?

Answer 31

Fine particles (soot), 100-2500 nm diameter

• Coarse particles (dust), 2500-105
  nm diameter

Question 32

Why do nanoparticles have properties different from

those for the same materials in bulk?

Answer 32

High surface area to volume ratio

Question 33

why are nanopartices useful as lubricant coatings and sun tan
cream and deodorants

Answer 33

l-reduce friction ,artificial joints and gears

cosmet-make no white marks.