Bonding, Structure and Properties

Question 1

What are substances made up of?

Answer 1

Atoms

Question 2

What are elements made up of?

Answer 2

Only on type of atom

Question 3

What does the top number of an element tell you?

Answer 3

The relative atomic mass and the total mass of the atom (proton and neutron number)

Question 4

What does the bottom number of an element tell you?

Answer 4

The atomic number and the number of protons and electrons

Question 5

What properties of metals are there?

Answer 5

Good conductors of electricity
High melting and boiling points
Strong

Question 6

What is a compound?

Answer 6

A substance in which 2 or more elements are chemically combined.

Question 7

What 3 types of chemical bonds are there?

Answer 7

Ionic
Metallic
Covalent

Question 8

What is ionic bonding?

Answer 8

The transfer of electrons from a metal to a non metal

Question 9

Explain the process of ionic bonding

Answer 9

Where an atom (usually a metal) loses electrons from its outer shell to become a positively charged ion, these electrons are donated to another atom (usually a nonmetal) which becomes a negatively charged ion. The strong attraction between the negative and positive charges form an ionic bond.

Question 10

What is covalent bonding?

Answer 10

The sharing of electrons between non metals

Question 11

What do atoms in metals form?

Answer 11

A regular giant lattice structure arrangement.

Question 12

What properties do metals have and why?

Answer 12

Metals are good thermal conductors due to the ions within the lattice being held closely together, so vibrations caused by heat are passed on easily.

Question 13

What allows the metals to conduct electricity?

Answer 13

The movement of delocalised electrons within the structure.

Question 14

What are the properties of a giant ionic structure?

Answer 14

High melting and boiling points due to strong bonds
Conduct electricity only when dissolved in water or molten so that the ions are free to move and carry an electric current.
Brittleness

Question 15

Describe the structure of a simple molecular structure.

Answer 15

Atoms form strong covalent bonds in small molecules, but the interactions between them are very weak.

Question 16

Properties of simple moleculars

Answer 16

Low melting and boiling points due to the weak forces. Most are gases or liquids at room temperature.
Don’t conduct electricity or dissolve in water.

Question 17

Describe the structure of a giant covalent structure.

Answer 17

Atoms are held in a giant covalent lattices by strong covalent bonds.

Question 18

Properties of giant covalent

Answer 18

Very high melting and boiling points due to all the atoms being held by covalent bonds.
They are insoluble in water
They don’t conduct electricity even when molten as they have no free electrons of ions.

Question 19

Properties of diamond

Answer 19

Very high melting point
Extremely hard (used for glass cutting and drills)
Electrical insulator

Question 20

Reasons for diamond

Answer 20

Carbon has 4 outer electrons and forms 4 covalent bonds. The strong bonds make it hard. It cannot conduct electricity as there are no ions or free electrons.

Question 21

Properties of graphite

Answer 21

Very high melting point
Very soft as a result used as a lubricant in machinery and in pencils.
Electrical conductor

Question 22

Reasons for graphite

Answer 22

Carbon atoms form 3 covalent bonds. Making up a layer of carbons in a hexagonal structure. This leaves a free electron per carbon which is free to move along the layers which let it conduct electricity.

Question 23

What is graphene made of?

Answer 23

A single layer of graphite molecules

Question 24

What can graphene be used for?

Answer 24

It’s so thin that it can be used in inks and electronics

Question 25

What are buckyballs made of?

Answer 25

60 carbon atoms joined together

Question 26

What can buckyballs be used for?

Answer 26

Can be used in medicine to transport drugs to specific parts of the body.

Question 27

What are carbon nanotubes used for?

Answer 27

Reinforcing materials e.g. tennis rackets

Question 28

What is the size of a nanoparticle?

Answer 28

1-100nm

Question 29

How big is a nanometre?

Answer 29

1x10^-9m

Question 30

Disadvantages of nanoparticles?

Answer 30

No research of the after effects and the properties are very different and unpredictable due to the change of size of the particles.

Question 31

What is nano-silver used for?

Answer 31

Has antibacterial properties which kill bacteria so they can be used in fridges to make food last longer.

Question 32

What is titanium dioxide used for?

Answer 32

Sunscreen, Titanium dioxide nanoparticles are so small they do not reflect visible light, so they don't appear white on the skin. They also block harmful UV lights.

Question 33

What is gold and silicon used for?

Answer 33

The particles absorb much more sunlight efficiently which is why they are useful in solar panels.

Question 34

What makes a smart material a smart material?

Answer 34

Smart materials have properties that change reversibly with a change in their surroundings.

Question 35

What is thermochromic?

Answer 35

Organic molecules in ink and paint that change colour as a result of temperature change.

Question 36

What is photochromic?

Answer 36

Organic molecules in ink and paint that change colour as a result of light especially UV. The light breaks bonds and the atoms are rearranged to form molecules of a different colour.

Question 37

What is a shape memory alloy?

Answer 37

Some alloys in particular some nickel/titanium and copper/aluminium/ nickel has two remarkable properties. Pseudoelasticity and shape-retention memory.

Question 38

What are shape memory polymers?

Answer 38

These are somewhere between thermoplastics and thermostats. When heated the polymer softens and it can be stretched and deformed. On cooling, it remains the deformed state. On being reheated it 'remembers' and returns to its original shape.

Question 39

Similarities between thermochromic and photochromic?

Answer 39

They both react to a stimuli.

Question 40

What is a hydrogel?

Answer 40

Cross linked polymers that have the ability to absorb or expel water when subjected to certain stimuli. They can be used in nappies. E.g. change in temperature or pH