C2.1

Question 1

Gases, liquids and solids with low melting points consist of what?

Answer 1

Simple molecules

Question 2

Why do simple molecular substances have low melting and boiling points?

Answer 2

Because the intermolecular forces between molecules are weak

Question 3

Why do giant covalent structures have high melting and boiling points?

Answer 3

Because there are strong covalent bonds between the atoms

Question 4

Why is diamond hard?

Answer 4

Because of the large number of strong covalent bonds

Question 5

What is the difference between the structure of diamond and graphite?

Answer 5

Diamond ~ Each carbon atom forms four covalent bonds with other carbon atoms
Graphite ~ Each carbon atom forms three covalent bonds with other carbon atoms

Question 6

Why is graphite soft?

Answer 6

~ Because there are weak intermolecular forces between layers
~ so the layers can slide over each other

Question 7

What is a giant ionic structure?

Answer 7

A regular structure held together by strong forces of attraction between oppositely charged ions

Question 8

Why do giant ionic structures have high melting and boiling points?

Answer 8

Because large amounts of energy are required to break the strong electrostatic bonds

Question 9

Why do ionic compounds conduct electricity when molten or in solution?

Answer 9

Because the charged ions are free to move about

Question 10

What are nanoparticles?

Answer 10

Tiny particles that can combine to form structures called nanostructures

Question 11

What are nanoparticles sensitive to?

Answer 11

~ Light
~ Heat
~ Magnesium

Question 12

Nanoparticles possess a high surface area in relation to what?

Answer 12

Their volume

Question 13

How are nanocomposites made?

Answer 13

By other materials being added to plastics

Question 14

How are alloys made?

Answer 14

By combining two or more different metals

Question 15

Why are alloys harder than pure metals?

Answer 15

~ Because they contain different sized atoms

~ This makes it difficult for layers to slide over each other

Question 16

Graphite is the only non-metal element to do what?

Answer 16

Conduct electricity

Question 17

What are fullerenes?

Answer 17

Hexagonal rings consisting of different numbers of carbon atoms joined by covalent bonds

Question 18

What are fullerenes made up of?

Answer 18

Simple molecules

Question 19

What are some uses of fullerenes?

Answer 19

~ Buckminster fullerenes can be used to deliver drugs into the body, or lubricants, or catalysts
~ Nanotubes can be used for reinforcing materials eg tennis racquets

Question 20

What are smart materials?

Answer 20

A type of nanostructure designed to have specific properties

Question 21

What are some examples of smart materials?

Answer 21

~ Lycra
~ Kevlar
~ Gore-Tex

Question 22

What is Lycra?

Answer 22

~ Stretchy material used in sport clothing

~ Doesn’t get damaged by sweat and detergents

Question 23

What is Kevlar?

Answer 23

~ Used to make body armour
~ Closely packed molecules and bonds form between adjacent molecules
~ Flexible and strong

Question 24

What is Gore-tex?

Answer 24

~ Keeps rain out but lets sweat pass through
~ Waterproof
~ Used for outdoor and sports clothing

Question 25

How big are nanoparticles?

Answer 25

1-100 nanometers

Question 26

Nanoparticles have a very large what?

Answer 26

Surface area to volume ratio

Question 27

What can nanoparticles be used for?

Answer 27

~ Catalysts ~ Cosmetics (sun cream, deodrant) ~ Medicine (drug delivery, antiviral and antifungal uses) ~ Construction to make items stronger and lighter ~ Computers ~ Coating (self cleaning windows)

Question 28

What is a chemical bond?

Answer 28

Transferring or sharing electrons in the outermost shell

Question 29

What is group 0 in the periodic table?

Answer 29

~ Noble gases ~ Full outer shell ~ Unreactive

Question 30

What is group 1 in the periodic table?

Answer 30

~ Alkali metals | ~ Produce ions with a charge of +1

Question 31

What is group 7 in the periodic table?

Answer 31

~ The halogens | ~ Produce ions called halides with a charge of -1

Question 32

In ionic bonding, when an atom gets a full outer shell it is said to have reached what?

Answer 32

A noble gas configuration

Question 33

What makes up the atomic mass?

Answer 33

Protons + neutrons

Question 34

What does the nucleus of an atom contain?

Answer 34

The protons and neutrons

Question 35

What do protons have a charge and mass of?

Answer 35

``` Charge = +1 Mass = 1 ```

Question 36

What do neutrons have a charge and mass of?

Answer 36

``` Charge = no charge Mass = 1 ```

Question 37

What do electrons have a charge and mass of?

Answer 37

``` Charge = -1 Mass = negligible ```

Question 38

What is equal in a stable atom?

Answer 38

The number of protons and electrons because they balance each other out

Question 39

What are isotopes?

Answer 39

Two atoms of the same element with the same number of protons but a different number of neutrons

Question 40

What type of bonding occurs in simple molecules?

Answer 40

Covalent bonding

Question 41

What group of elements do ions have the same electronic structure as?

Answer 41

Noble gases, group 0

Question 42

What bond do two non metals form?

Answer 42

Covalent bond

Question 43

What bond does a metal and a non metal form?

Answer 43

Ionic bond

Question 44

What are metallic bonds?

Answer 44

The attraction between delocalised electrons and positive metal ions

Question 45

Why do ionic compounds have no overall charge?

Answer 45

Because there are the same number of positively charged ions and negatively charged ions