UNIT 1 - BONDING

Question 1

WHAT ARE IONIC BONDS ?

Answer 1

Bonds between metals and non-metals

Question 2

HOW ARE IONIC BONDS FORMED ?

Answer 2

METALS LOSE ELECTRONS AND NON-METALS LOSE ELECTRONS IN ORDER TO ACHIEVE A FULL OUTER SHELL OF ELECTRONS

Question 3

WHAT ARE THE PROPERTIES OF IONIC COMPOUNDS ?

Answer 3

HIGH MELTING AND BOILING POINT
BRITTLE
CONDUCT WHEN MOLTEN
SOLUBLE IN WATER

Question 4

WHY DO IONIC COMPOUNDS HAVE HIGH MELTING AND BOILING POINTS ?

Answer 4

A lot of heat energy is required to break the strong ionic bonds / electrostatic forces between ions

Question 5

WHY ARE IONIC COMPOUNDS BRITTLE ?

Answer 5

When force is applied to an ionic crystal, the layers shift bringing ions of the same charge together they repel causing the crystal to shatter

Question 6

WHY DO IONIC COMPOUNDS CONDUCT WHEN MOLTEN ?

Answer 6

In a solid ions cannot move so cannot carry electricity
When molten or dissolved ions move to carry current

Question 7

WHY ARE IONIC COMPOUNDS SOLUBLE IN WATER ?

Answer 7

Water molecules are slightly charged and so are able to break apart ions in ionic lattice

Question 8

HOW ARE COVALENT BONDS FORMED ?

Answer 8

Electrons are shared between non-metals to complete a full outer shell

Question 9

WHAT IS BONDED IN A COVALENT BOND ?

Answer 9

Non-metals

Question 10

PROPERTIES OF COVALENT BONDS ?

Answer 10

LOW MELTING AND BOILING POINT
POOR CONDUCTORS

Question 11

WHY DO COVALENT BONDS HAVE A LOW MELTING AND BOILING POINT ?

Answer 11

Covalent bonds are strong but the intermolecular forces are weak, meaning they can be broken with little heat energy

Question 12

WHY ARE COVALENT COMPOUNDS POOR CONDUCTORS ?

Answer 12

They cannot conduct as they have no mobile charged particles

Question 13

WHAT IS THE STRUCTURE OF DIAMOND ?

Answer 13

4 (c-c) bonds, no free electrons

Question 14

WHAT ARE THE PROPERTIES OF DIAMOND ?

Answer 14

HIGH MELTING AND BOILING POINT
STRONG
ELECTRIC INSULATOR

Question 15

WHY DOES DIAMOND HAVE A HIGH MELTING AND BOILING POINT ?

Answer 15

Each carbon forms 4 (c-c) bonds with strong covalent bonds which require high energy to break

Question 16

NAME THREE CARBON ALLOTROPES

Answer 16

CARBON
GRAPHITE
GRAPHENE

Question 17

HOW IS GRAPHITE STRUCTURED ?

Answer 17

Each carbon forms 3 (c-c) bonds
Free electrons between layers
Structured in layers
Hexagonal pattern

Question 18

WHAT ARE THE PROPERTIES OF GRAPHITE ?

Answer 18

HIGH MELTING POINT
SLIPPERY
GOOD CONDUCTOR

Question 19

WHY IS GRAPHITE SLIPPERY

Answer 19

Layers are strong but layers are held together by weak intermolecular forces
Layers slide over one another when pressure is applied

Question 20

WHY IS GRAPHITE A GOOD CONDUCTOR ?

Answer 20

Delocalised electrons between layers can carry electrical current

Question 21

HOW IS GRAPHENE STRUCTURED ?

Answer 21

A single layer of carbon atoms
3 (c-c) bonds + free electrons

Question 22

WHAT ARE THE PROPERTIES OF GRAPHENE ?

Answer 22

STRONG
BEST KNOWN CONDUCTOR

Question 23

WHAT ARE NANOTUBES MADE FROM ?

Answer 23

Graphene rolled into a tube of carbon atoms
Delocalised electrons inside

Question 24

WHAT ARE THE PROPERTIES OF NANOTUBES ?

Answer 24

STRONG
BEST KNOWN CONDUCTOR
SLIPPERY - Tubes of electrons slide over eachother easily

Question 25

WHAT IS BUCKMINSTER FULLERENE

Answer 25

Carbon Cages 3 (c-c) bonds The fourth delocalised electron is in the middle Used in drug delivery

Question 26

HOW ARE METALLIC BONDS FORMED ?

Answer 26

In solid metals, metal atoms lose their outer shell of electrons These electrons become delocalised and move freely around the lattice Metal is held together by the strong electrostatic attractions between metal ions (+) and electrons (-)

Question 27

WHAT ARE THE PROPERTIES OF METALS ?

Answer 27

MALLEABLE DUCTILE SHINY STRONG AND INSOLUBLE IN WATER GOOD CONDUCTOR HIGH MELTING AND BOILING POINT

Question 28

WHY ARE METALS MALLEABLE AND DUCTILE ?

Answer 28

Metals can be hammered as electrons move with the metal ions keeping the bonds intact as layers move.

Question 29

WHY ARE METALS GOOD CONDUCTORS ?

Answer 29

Free electrons can carry current

Question 30

WHY DO METALS HAVE A HIGH MELTING AND BOILING POINT ?

Answer 30

Lots of heat energy is required to break the the strong metallic bonds between metal ions and delocalised electrons.

Question 31

NAME FIVE SMART MATERIALS

Answer 31

HYDROGELS SHAPE MEMORY ALLOYS SHAPE MEMORY POLYMERS PHOTOCHROMIC PIGMENTS THERMOCHROMIC PIGMENTS

Question 32

WHAT IS A SMART MATERIAL ?

Answer 32

Smart materials have unique properties that are triggered by certain environmental conditions

Question 33

WHAT ARE PHOTOCHROMIC PIGMENTS ?

Answer 33

Pigments that change colour depending on light intensity i.e. sunglasses

Question 34

WHAT ARE THERMOCHROMIC PIGMENTS ?

Answer 34

Pigments that change colour depending on the temperature i.e. baby spoons and novelty mugs

Question 35

WHAT IS A SHAPE MEMORY POLYMER ?

Answer 35

A plastic that returns to its original shape upon heating i.e. gum shields and car bumpers

Question 35

WHAT IS A SHAPE MEMORY ALLOY ?

Answer 35

An alloy that returns to its original shape upon heating i.e. braces wires

Question 35

WHAT IS A HYDROGEL ?

Answer 35

A superabsorbant polymer that can absorb 1000x its own volume in water i.e. nappies

Question 36

NAME TWO EXAMPLES OF NANOPARTICLES ?

Answer 36

SILVER NANOPARTICLES TITANIUM DIOXIDE

Question 37

WHAT ARE SILVER NANOPARTICLES USED FOR ?

Answer 37

Anti-viral, bacterial and fungal Used in cleaning surgical equipment and coating fridges to stop odour

Question 38

WHAT ARE TITANIUM DIOXIDE NANOPARTICLES USED FOR ?

Answer 38

They are transparent and repel water and UV rays Used in transparent sunscreens and self-cleaning windows

Question 39

WHAT ARE THE ISSUES LINKED TO NANOPARTICLES ?

Answer 39

Nanoparticles are so small that they can be inhaled or pass straight through the skin into the blood We do not know the long term affects of these particles on our health.