C2 : Bonding, Structure and the Properties of Matter

What are the 3 types of bonds?

• Ionic

• Covelant

• Metallic

What is an ion + why does this happen?

When an atom gains or loses electrons to gain a full outer shell and become stable

What are the 3 types of bonds?

• Ionic

• Covelant

• Metallic

What is an ion + why does this happen?

When an atom gains or loses electrons to gain a full outer shell and become stable

What does ionic bonding occur between + what is formed in terms of ions?

• Metals and non-metals react together

• The metal loses electrons forming a positive ion + the non-metal gains electrons forming a negative ion

Which groups are most likely to form ions?

1,2,6,7

What are group 1 + 2 elements, do they gain or lose electrons + what do they form?

• Metals

• Lose electrons

• Positive ions

What is a positive ion called?

Cation

What are group 6 + 7 elements, do they gain or lose electrons + what do they form?

• Non-metals

• Gain electrons

• Negative ions

What are negative ions called?

Anions

What charge ions do groups 1,2,6,7 form? (4)

• Group 1 → 1+ ions

• Group 2 → 2+ ions

• Group 6 → 2- ions

• Group 7 → 1- ions

Write the half equation for sodium gaining a full outer shell (Na → group 1)

Na → Na⁺ + e^-

Write the half equation for magnesium gaining a full outer shell (Mg → group 2)

Mg → Mg²⁺ + 2e^-

Write the half equation for chlorine gaining a full outer shell (Cl → group 7)

Cl + e^- → Cl^-

Write the half equation for oxygen gaining a full outer shell (O → group 6)

O + 2e^- → O^2-

What happens to the electrons in ionic bonding?

Electrons are transferred

What diagram represents ionic bonding?

Dot and cross diagrams

Draw a dot and cross diagram for sodium chloride (NaCl)

(Na → group 1) (Cl → group 7)

Draw a dot and cross diagram for magnesium oxide (MgO)

( Mg→ group 2 ) ( O→ group 6 )

Draw a dot and cross diagram for magnesium chloride (MgCl₂)

( Mg→ group 2 ) ( Cl→ group 7 )

Draw a dot and cross diagram for (Na₂O)

( Na→ group 1 ) ( O→ group 6 )

What is an ionic compound?

A giant structure of ions

What are ionic compounds held together by?

Strong electrostatic forces of attraction between oppositely charged ions

What direction do the electrostatic forces in a ionic compound act in + what is this called?

The forces act in all directions between oppositely charged ions and this is called ionic bonding

What is the ionic compound structure called?

A giant ionic lattice

What are the 2 ways to a draw giant ionic lattice?

• Space filling

• Ball and stick diagrams

Draw a ball and stick diagram + label the diagram

Draw a space filling diagram and label the diagram

What are the properties of ionic compounds + why? (3)

• High melting + boiling points → strong electrostatic forces which need a lot of energy to overcome

• When solid, can’t conduct electricity → ions aren’t free to move

• When molten (melted) or dissolved in water, can conduct electricity → ions are free to move and will carry charge

What does covalent bonding occur between?

• Non metal and a non metal

What happens to the electrons in covalent bonding?

The electrons on the outer shell are shared

What 3 diagrams are used to draw covalent bond?

• Dot and cross diagrams

• Displayed formula

• 3D model

For covalent bond what happens to the electrons in a dot and cross diagram?

They overlap

Draw a dot and cross diagram for ammonia NH₃

_{(Nitrogen → group 5) (Hydrogen → group 1)}

(both are fine)

Draw the displayed formula for ammonia NH₃

_{(Nitrogen → group 5) (Hydrogen → group 1)}

Draw a 3D model for ammonia NH₃

_{(Nitrogen → group 5) (Hydrogen → group 1)}

Name the 8 simple molecular substances

• Hydrogen

• Chlorine

• Oxygen

• Nitrogen

• Methane

• Water

• Hydrogen chloride

• Ammonia

Draw a dot and cross diagram for

(Hydrogen → group 1)

Draw a dot and cross diagram for

(Chlorine → group 7)

Draw a dot and cross diagram for

(Oxygen → group 6)

Draw a dot and cross diagram for

(Nitrogen → group 5)

Draw a dot and cross diagram for

(Carbon → group 4) (Hydrogen → group 1)

Draw a dot and cross diagram for

(Hydrogen → group 1) (Oxygen → group 6)

Draw a dot and cross diagram for

(Hydrogen → group 1)(Chlorine → group 7)

What are the properties of simple molecular compounds? (4)

• Low melting and boiling points

• Gases or liquids at room temperature

• They do not conduct electricity because there are no free ions to carry charge

• The bigger they get, the stronger the intermolecular forces get so their melting + boiling points increase

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

Because they have weak intermolecular forces between them which do not require a lot of energy to break

What is a polymer?

A long molecule made up of many monomers

What bond are polymers joined by?

Covalent bonds

How are polymers represented?

With a repeating unit

Draw poly(ethene) + label it

What are the properties of polymers?

Solid at room temperature as intermolecular forces are relatively strong

In giant covalent structures what are the atoms bonded by?

Strong covalent bonds

What are the properties of giant covalent structures? (3)

• Solids

• Vey high melting and boiling points

• Don’t conduct electricity

Give 3 examples of giant covalent structures

• Diamond

• Graphite

• Silicon dioxide (silica)

Draw + describe the structure of diamond

Each carbon atom forms four covalent bonds in a very rigid giant covalent structure

Draw + describe the structure of graphite

• Each carbon forms 3 covalent bonds to create layers of hexagons + each carbon atom has a delocalised electron

• Made up of layers of graphene which are held together weakly

What is graphene + how big is it?

A sheet of carbon atoms joined together in hexagons + is one atom thick

What are the properties of graphite? (6)

• High melting + boiling points → covalent bonds need a lot of energy to break them

• Conduct electricity → have a delocalised electron

• Conduct thermal electricity → particles free to move

• Light

• Slippery

• Soft

Draw + describe the structure of silicon dioxide (silica) + what is it also known as?

• Silicon and oxygen bonded together with covalent bonding

• Also know as sand

What is are allotropes?

Different structural forms of the same elements in the same physical state

Give the 3 allotropes of carbon

• Diamond

• Graphite + Graphene

• Fullerenes

What are the properties of diamond? (3)

• Hard → made up of carbon atoms each having 4 covalent bonds making diamond

• High melting point → strong covalent bonds

• Doesn’t conduct electricity

What are fullerenes?

Molecules of carbon shaped like closed tubes or hallow balls

What shapes can fullerenes be made up of? (3)

• Hexagons

• Pentagons

• Heptagons

What was the first fullerene discovered calls + what is it molecular formular and what shape is it?

Buckminsterfullerene (C₆₀) which has a spherical shape

What are the uses of fullerenes? (3)

• Pharmaceutical delivery → ‘cage’ other molecules such as a drug which would be delivered into the body

• Lubricants

• Catalysts

What are carbon nanotubes?

Fullerenes shaped into long cylinders

What are the properties of carbon nanotubes? (2)

• Have very high tensile stretch (can be stretched without breaking)

• Conductors of heat and electricity

What is nanotechnology + when can it be used? (2)

Technology that uses nanotubes

• used in electronics

• or to strengthen materials without add much weight such as in tennis rackets

What does metallic bonding happen between?

Metal and metals

What happens to the electrons in metallic bonding?

They are free to move

What is the structure of metals?

A giant structure of atoms arranged in regular layers

What are the properties of metals? (5)

• Solid at room temperature

• High melting + boiling points

• Conduct electricity + heat → sea of delocalised electrons are free to move

• Malleable → can be bend and shaped

• Layers are able to slide over each other

What is an alloy?

A mixture of metals

What is the disadvantage of pure metals + how can this problem be fixed?

Pure metals are too soft so they can be mixed with other metals to become harder → different sized atoms when joined together distort layer making it more difficult to slide over each other

What are the 3 states of matter?

• Solid

• Liquid

• Gas

What 3 factors do forces of attraction depend on?

• Material (structure of substance + type of bonds)

• Temperature

• Pressure

How do the particles behave in a solid? (3)

• Strong forces of attraction between particles → close together which form a regular giant arrangements

• Particles don’t move from their positions → keep definite shape + volume

• Vibrate in fixed positions

How do the particles behave in a liquids? (3)

• Weak forces of attraction between particles → move past each other

• Have a definite volume but don’t keep a definite shape

• Particles move in different directions

How do the particles behave in a gases? (3)

• Weak forces of attraction between particles → move past each other + far apart

• Don’t have a definite volume or a definite shape

• Particles move in different directions

What are the 4 state symbols?

• Solid → (s)

• Liquid → (l)

• Gas → (g)

• Aqueous (in solution) → (aq)

How would you predict the state of a substance? (3)

• Temperature below melting → Solid

• Temperature above boiling → Gas

• Temperature in between → Liquid

What is the diameter of coarse particles, fine particles + nanoparticles? (in nm)

• Coarse particles (PM₁₀, or dust) → between 2500 to 10,000 nm

• Fine particles (PM_2.5) → between 100 to 2,500 nm

• Nanoparticles → between 1 to 100 nm

What happens to a particles surface area : volume ratio if the particle size decreases by 10?

The surface area : volume ration increases by 10

What are the uses of nanoparticles? (6)

• Medicine

• Sun creams

• Cosmetics

• Deodorants

• Electronics

• Catalysts

What are the risks of using nanoparticles?

When used in cosmetic products or sun creams nanoparticles could be absorbed into the body and the dangers of them are unknown

• a) Solid

• b) Liquid

• c) Liquid

• d) Gas

What are the pros + cons of dot and cross diagrams? (2)

• Can see where electrons have moved from and to

• Don’t tell us the shape of the molecule

What are the cons of 2D stick diagrams diagrams? (2)

• The covalent bond is represented as a stick so we can’t tell which electrons in the bond came from which atom

• Don’t tell us the shape of the molecule

What are the pros + cons of ball and stick diagrams? (3)

• Allow is to see the ions in 3 dimensions

• The ions are widely spaced which is inaccurate

• Gives a mistaken impression about the size of the structures

What are the pros + cons of space filling diagrams? (3)

• Show how closely packed ions are

• Difficult to see all the atoms clearly

• Gives a mistaken impression about the size of the structures

What is the empirical formula?

The simplest whole number ratio of atoms of each element in a compound

Work our the empirical formula of

CH₂

(Atomic mass for Hydrogen = 1) (Atomic mass for Oxygen = 16)