Topic 2 Bonding And Structure

Question 1

What is an ion

Answer 1

A charged particle they can be single atoms or a group

Question 2

Why do atoms form ions

Answer 2

To get a full outer shell like a noble gas and a stable electronic configuration
Atoms with full outer shells are very stable

Question 3

How does a metal react

Answer 3

When metals form ions they lose electrons from their outer shell to form positive ions to get a full outer shell

Question 4

How do non metals react

Answer 4

When non metals form ions they gain electrons into their outer shell to form negative ions

Question 5

How do u measure the charge

Answer 5

It is the number of electrons gained or lost

The valency is the same as the size of the charge of the atom

Question 6

How do metals and non metals react together to make a bond

Answer 6

Metal atom loses an electron to form a positively charged ion
And non metals gain these electrons to form negatively charged ions

Question 7

How are ions attracted to each other

Answer 7

These oppositely charged ions are strongly attracted to each other by electrostatic attraction and this is the ionic bond

Question 8

Give two examples of ionic bonds

Answer 8

NaCl and MgO

Question 9

What is an ionic compound

Answer 9

They only happen between metals and non metals
They for between millions of positive and negative ions which form millions of ionic bonds which form a giant ionic lattice
The ions form a closely packed regular lattice arrangement and these have very strong electrostatic attraction acting in all directions

Question 10

What properties do ionic compounds have

Answer 10

They all have high melting and boiling points due to the many string bonds between the ions. It takes a lot of energy to overcome this attraction
When it’s a solid the ions can’t move around so they can’t conduct electricity

Question 11

How can ionic compounds conduct

Answer 11

They can conduct when molten or dissolved in water because the electrostatic charges are broken and the ions are free to move and carry current

Question 12

Features of covalent bonding

Answer 12

When non metals atoms bond together they share pairs of electrons
The positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces making covalent bonds very strong

Question 13

Give examples of covalent bonding simple molecular

Answer 13

H2 Cl2 NH4

Question 14

What are the properties of simple molecular structures

Answer 14

They are usually covalent bonds
The forces of attraction within these molecules are held by strong covalent bonds but the forces between the molecules are weak ( van der waals)
To melt or boil you only need to break the intermolecular forces and not the covalent bond so melting and boiling points are low because the molecules are easily parted
Most molecular substances are gases or liquids at room temperature
As the mass increases the strength of intermolecular forces increases so their is a higher melting and boiling point so more energy is needed to break them

Question 15

Do molecular compounds conduct

Answer 15

They aren’t charged and there aren’t any free electrons or ions

Question 16

How do you measure strength between the atoms

Answer 16

The size of the strength between atoms depends upon the type of bonding and nature of the atom

Question 17

Features of giant covalent structures

Answer 17

They are bonded to each other by strong covalent bonds
They have very high melting and boiling points a lot of energy is required to break the bonds
They don’t conduct electricity not even when molten apart from graphite

Question 18

Features of diamond

Answer 18

Diamond has a giant. covalent structure made up of carbon atoms that each form four covalent bonds . This makes diamond really hard
Those strong covalent bonds take a lot of energy to break and this gives diamond a very high melting point
It doesn’t conduct electricity because it has no free electrons or ions

Question 19

Give features of graphite

Answer 19

Each carbon atom forms three covalent bonds creating sheets of carbon atoms arranged in hexagons
There are t any covalent bonds between the layers only weak van der waals so they’re free to slide over each other . This makes graphite soft and slippery and so graphite is a good lubricating material
Graphites got a high melting point the covalent bonds in the layers need energy to break
Only three out of each carbons four outer electrons are used in bonds so each carbon has an electron delocalised
So graphite conducts electricity and thermal energy

Question 20

Features of graphene

Answer 20

It’s one layer of graphite
It is a sheet of carbon atoms joined together in hexagons
The sheet is one atom thick
Network of covalent bonds make it strong and light so can be added to composite materials
Like graphite it contains delocalised electrons so can be used for electronics
Higher tensile strength than steel

Question 21

Features of fullerenes

Answer 21

Molecules of carbon shaped like closed tubes or hollow spheres
Carbon atoms arranged in hexagons mainly
Used to cage other molecules . Fullerene structures form around another atom or molecule which is trapped inside. This could be used to deliver drugs into the body
Have a large surface area so help make catalysts
Make good lubricants

Question 22

Features of carbon nanotubes

Answer 22

Fullerenes can form nanotubes

Ratio between length and diameter of nanotubes is very high

Conduct electricity and thermal energy

High tensile strength

Used in electronics
Or strengthen materials without adding weight like tennis racquets

Question 23

Describe metallic bonding

Answer 23

Consist of a giant structure
The electrons in the outer shell of the metal atoms are delocalised so they can carry current and metals are good conducters of heat and electricity
There are strong forces of electrostatic attraction between the positive metal ions and shared negative electrons
These forces of attraction hold the atoms together in a regular structure and are known as metallic bonding . Metallic bonding is very strong
Substances held together by metallic bonding include metallic elements and alloys
It’s the delocalised electrons in the metallic bonds which produce all the properties of metals
Electrostatic forces are strong so they have high melting and boiling points needed lots of energy
Most compounds with metallic bonds are solid at room temp

Question 24

Why are metals malleable

Answer 24

Layers of atoms in a metal can slide over each other making metals malleable this means they can be beet or hammered

Question 25

What is an alloy

Answer 25

Alloys are a mixture of two or more metals or a metal and another element.
Pure metals are too soft, lose their shape and can be scratched easily. The new metal atoms will distort the layers of metal atoms making it more difficult for them to slide over each other this makes alloys harder than pure metals

Question 26

How does a solid behave

Answer 26

Sting forces of attraction between particles holds them together in fixed positions to form a regular lattice arrangement
Particles don’t move from their positions and keep a definite shape
They vibrate when heat is added causing solids to expand

Question 27

Liquids behave

Answer 27

Weak force of attraction between particles
Free to move but stick close
Definite volume but not shape
Constantly moving
Heat causes them to move faster causing them to separate

Question 28

How gases behave

Answer 28

Very weak attraction 
Free to move and far apart
Dont keep a shape or volume 
Constantly move around 
Expand when heated or pressure increases

Question 29

Features of nano particles

Answer 29

They are really small 1-100nm
As materials are made into smaller pieces their surface area increases
High surface to volume ratio
Many have different properties different from those for the same materials in bulk because of their high surface to volume ratio
Smaller quantities are needed to be effective than for materials with normal particle sizes .

Question 30

What could nanoparticles be used for

Answer 30

High surface to volume ratio could help make new catalysts
Controlled drug delivery
Some co duct so used in electronics
Silver nanoparticles have antibacterial properties. They can be added to polymer fibres that make surgical masks wound dressings and added to deodorants
Fabrics to prevent growth of bacteria
Cosmetics
Titanium dioxide nanoparticles are used in sun block and reflect UV light

Question 31

Why are nanoparticles bad

Answer 31

Cell damage in body
Damage environment
Damage lungs