C3-Structure And Bonding Flashcards
What is an ionic bond
Ionic bond is force that hold them together between a metal and a non metal and ionic compound is everything.
What are ionic compounds held by
Ionic compounds are held by strong electrostatic forces of attraction by there oppositly charge ionic bonding.Between a metal and a non metal
Ionic charges Group 1,2,3
1+,2+,3+
Ionic charges group 5,6,7
3-,2-,1-/-
Ammonium
NH4+
+1 ion
Nitrate
No3 -
-1 ionic charge
Sulfate
So4 2-
2- ionic charge
Carbonate
Co3
2- ionic charge
Phosphate
Po4
3- ionic charge
Zinc
Zn
2+ ionic charge
States of matter
Solid,liquid,gas,aqueos
Properties of Ionic solids
Fixed in position in a giant lattice.Vibrate but no movement.Cannot conduct electricity
State features of Molten ionic compounds
High temperatures provides enough energy to overcome the many strong attractive forces between ipns.Ions are free to move.
Conducts electricity
Ionic compound in solution
Water molecules seperate ions from the lattice.Ions are free to move around within the solution.
Conducts electricity
When do ionic compounds conduct electricity
When they are molten or dissolved in water.This is because their ions can then become mobile and can carry charge throughout the liquid
Define Lattice
Defintion-A repeating regular arrangement of atoms/ions/molecules. This arrangement occurs in crystal structures.
The electrostatic forces of attraction between the oppositely charged ions in an ionic compound are veru strong. operating in all directions.
What is a covalent bond
A bond between a non metal and non metals atoms where they share electrons
What is an alloy
a mixture of two or more elements, at least one of which is a metal
What is a delocalised electrom
bonding electron that is no longer associated with any one particular atom
What is a dot and cross diagram
a drawing to show only the arrangement of outer shell electrons of the atoms or ions in a substance
What is fullerene
form of the element carbon that can exist as large cage-like structures, based on hexagonal rings of carbon atoms
What is a giant covalent structure
a huge 3D network of covalently bonded atoms
What is a giant lattice
a huge 3D network of atoms or ions
What is the intermolecular force
the attraction between the individual molecules in a covalently bonded substance
What is a liquid
substances that have a fixed volume, but they can flow and change their shape
What is an ionic bond
the electrostatic force of attraction between positively and negatively charged ions between metal and non metals
What is particle theory
The theory which models the three states of matter by representing the particles as small solid spheres. Particle theory can help to explain melting, boiling, freezing and condensing.
What is a polymer
a substance made from very large molecules made up of many repeating units
What is the state of matter
the forms in which matter can exist. A substance can be solid, liquid or gas
How are ionic compounds held together?
• They are held together in a giant lattice.
• It’s a regular structure that extends in all directions in a substance.
• Electrostatic attraction between positive and negative ions holds the structure together.
How are ionic compounds formed? Explain in terms of MgO case.
Reaction of a metal with a non-metal.
Electron transfer occurs - metal gives away its outer shell electrons to non-metal.
Mg is in Group Il, so has 2 available outer shell electrons.
O is in Group VI, so can accept 2 electrons to get a full outer shell configuration.
Mg becomes Mg?* and O becomes O2- (oxide).
How do intermolecular forces change as the mass/size of the molecule increases?
They increase. That causes melting/boiling points to increase as well (more energy needed to overcome these forces).
What are thermosoftening polymers
Thermosoftening polymers - special type of polymers; they melt/soften when heated. There are no bonds between polymer chains. Weak intermolecular forces ensure that the structure is solid at room temperature. These forces are overcome with heating - polymer melts.
Describe and explain the properties of allotropes of carbon. Diamond
Diamond
- four, strong covalent bonds for each carbon atom
- very hard (Strong bonds)
- very high melting point (strong bonds)
- does not conduct (no delocalised electrons)
-Giant covalent structure.
Describe and explain the properties of the allotropes of carbon,fullerenes
Fullerenes
- hollow shaped molecules
- based on hexagonal rings but may have
5/7-carbon rings
- C6o has spherical shape, simple molecular structure (Buckminsterfullerene)
-Have a large surface area to volume ratio
What is metallic bonding
Metallic bonds are the chemical bonds between positively charged cations, sharing delocalised electrons amongst a giant lattice structure/atoms in a metal
Describe the properties and structure of metal
Giant structure of atoms/ions
High melting/boiling points (strong forces of attraction)
- Good conductors of heat and electricity (delocalised electrons)
- Malleable, soft (layers of atoms can slide over each other whilst maintaining the attraction forces)
Why are alloys harder than pure metals?
different sizes of atoms distorts the layers, so they can’t slide over each other, therefore alloys are harder than pure metals
Properties of simple covalent bonds
Low melting point and boiling,does not conduct electricity when solid pr molten.
Propertys of ionic bonding
High melting and boiling due to strong forces between oppositley charged ions,no conductivity when solid but when molten conductablw
Properties of giant covalent bonds
High melting and boiling points,diamond and sand poor(cannot move),graphite conduct when solid as delocalised electrons can move,when molten poor conductor
Properties of mettalic
High melting and boiling points,good conducter when solid and molten
Limitations of the simple model
No forces between spheres and atoms,molecules and ipns are solid spheres-this is not true
What does the amount of energy needed to change state from solid to liquid or liquid to gas depend on?
The strength of the forces between the particles of the substance. The nature of the particles involved depends on the type of bonding and the structure of the substance. The stronger the forces between the particles the higher the melting point and boiling point of the substance
A pure substance will melt or boil at…?
A fixed temperature.
A mixture will melt over a range of temperatures.
What is nanoscience
Science that studies that are 1-100nm in size
Why do nanoparticles have properties different from those for the same materials in bulk
Higher surface area to volume ratio
Properties of Metallic bonding
High melting and boiling points,good conductors of electricity,malleable and ductile,strong
Properties of small molecules
that have low boiling and melting.
• They have weak intermolecular forces between the molecules. These are broken in boiling or melting, not the covalent bonds.
• The intermolecular forces increase with the size of the molecules, so larger molecules have higher melting and boiling points.
• dont conduct electricity, because small molecules do not have an overall electric charge.
Dtrong covlanet bonds
Uses of nanoparticles
They have a high surface area to volume ratio, and therefore would make good catalysts.
• They can also be used to produce highly selective sensors.
• Nanotubes could make stronger, lighter building materials.
• New cosmetics, e.g sun tan cream and deodorant. They
• Lubricant coatings, as they reduce friction. These can be used for artificial joints and
Nanotubes conduct electricity, so can be used in small electrical circuits for
possible disadvantages: there are some concerns that nanoparticles may be toxic to people. They may be able to enter the brain from the bloodstream and cause harm.
Possible risks of nanoparticles
Due to there large surface area If a spark is made by accident near a large quantity of the catalyst, there could be a violent explosion.
Higher risk of finding their way into the atmosphere. In general, Breathing in tiny particles could damagethe lungs.
How to calculate surface area to volume ratio
Sa/V
Sa=basexheightx6cm^2
V=basexheightxwidth
1 nanometre
1x10-9 meters
Why does nano particles save money
Its costs less as you need a smaller amount of it due to its larger suface area to volume ratio
Structure of the Bonding between metals
Closely packed together,delocalised electrons are free to move throughout thr giant mettalic lattice
What is a metal bonding considered with delocalised electrons in it
A sea of delocalised electeons
Formula for diamond,graphite,buckminsterfullerene,graphene
Diamond=c,graphite=c,buckminsterfullerene=c60,graphenevc
Explain the giant covalent structure of graphite
Giant layers of covalently bonded carbon atoms.No covalent bonds between layers.This means they can slide over eachother.
For simple molecules describe its forces within
Strong covalent bonds but weak force between molecules(weak intermolecular force
Charge of simple molecules
No overallcharge
What is a simple molecular substance
Substances which are made up of molecules containing a few atoms joined together by covalent bonds.
Common examples of simple molecules
H2-hydrogen
O2-oxygen
Ch4-methane
Cl2-Chlorine
N2-Nitrogen
H20-Water
Hcl-Hydrogen Chloride
Properties of simple molecular substances
Low melting and boiling points,do not conduct electricity,weak intermolecular forces,soft,usually a gas or liquid at room temperatures
Explain why oxygen is a gas at room temperature
Because of irs weak intermolecular forces are broken allowing them to move freely.
What state is a polymer at room temperature
Solid
What is an allotrope
Different structural form of the same element in the same physical state eg.diamond
Explain and show the properties of the allotropes of carbon graphite
Graphite
- three covalent bonds for each carbon atom
- contains layers of hexagonal rings
- high melting point
- layers free to slide as weak intermolecular forces between layers; soft, can be used as a lubricant
- conduct thermal and electricity due to one delocalised electron per each carbon atom
-Sheets of carbon
-Has three out of the four carbons used so it has a extra carbon which is delocalised and can move so therefore it can conduct electricity
Describe and explain the properties of the allotropes of carbon-graphene
Graphene - a single layer of graphite joined together in hexagons
-Very strong covalent bonds
-Very light
-Can be added to a composite material to improve their strength without adding much weight
-Contains a delocalised electron so therefore can conduct electricity
-Potential to be used in electrons
How strong the forces of attraction depends on three things
-the material
-temperature
-pressure
Properties of solids
Strong forces of attraction,form a very regular lattice arangement
-particles do not move from their positions
-particles vibrate in a fixed position
Properties of liquids
Weak forces of attraction,tend to stick closely to eachother,Have a definite volume but dont keep a definite shape,particles are constantly moving with a random motion,hotter the liquid the faster they move
What is an aqueous solution
aqueous solution” is a solution in which water is the solvent, such as salt dissolved in water
Properties of gases
Weak forces of attraction,free to move,don’t keep a definite shape or volume,move constantly,gases either expand when heated or their pressure increased
Defintion of physical change
The changing of a particles arrangement or their energy
What happens when a solid is heated
When a solid is heated the particles vibrate more,which weakens the forces of attraction,at certain temperatures called the melting point the particles have enough energy to break free.This is when it turns into a liquid,when its heated again it gets even more energy,Which makes it move even fastee and then this breaks its bond again passing its boiling point turning into a gas
What happens when a gas is cooled
When a gas is cooled the particles no longer have enough energy to overcome the forces of attraction,bonds form between the particles,at the boiling point so many bonds have formed between the gas particles that the gas condenses and becomes a liquid,when a liquid cools the particles have even less energy and then once it has not enough energy to overcome the attraction so more bonds are formed then it turns into a solid and is known as frozen/freezing
What is it if a substance is below the melting point of a substance
Solid
What if a substance is above the boiling point
Gas
If its between two points
Liquid
What happens if a particles size decreases
The size of their surface area in relation to their volume will increase
Features of nanoparticles
Durable,high surface area to volume ratio,extremely small,helps make new catalysts,some conduct electricity,
Features of pure metals
-Layers
-Delocalised electrons
-Slide over eachother
-Soft
Features of alloys
-Distorted layers
-Cannot slide over each other
-Hard
-Not conductive
Features of ionic compounds
Structure-Giant ionic lattice,forces act in all directions,held together by strong electrostatic forces of attraction.
Properties:High melting point,high boiling point,only conducts when molten or dissolved.This is because the ions need to be free to move
Features of simple covalent structures
Structure-Covalent bonding
Properties-Low melting points,low boiling points,do not conduct,gas/liquid at room temperature
Properties of Giant covalent compounds
Structure-Giant covalent structure
-Properties-High melting points,high boiling points,do not conduct,do not disolve
Comparing graphite to diamond
Similarties:Both made of pure carbon,both giant covalent structures
Differences:Graphite made out of 3 carbon bonds wheras diamond is made out of 4.Graphite is soft and dimond is hard
Similarites and differences of carbon nanotubes and buckminsterfullernes
Similarites:carbon allotropes,3 carbon bonds,both hard,both be used as drug delivery
Differences:Bucky balls can be used as lunricants,reinforcmants
Structure of polymers
Made of up smaller units-monomers
Features of metallic bonding
Strong,delocalised electrons,regular pattern,sea of delocalised electrons
What is a molecular formula
The actual ratio of atoms of each element present in a compound
What is happening with temperature and energy describe the movement of particles at the melting point of a substance? -
When a solid is heated to its melting point, the kinetic energy of the particles tends to increase and their movement also starts increasing. The bond present between the particles starts breaking and these particles start vibrating at their own position.
What factors effect rate of evaporation?
Temperature: When the temperature is high, the kinetic energy of the water particles increases, leading to the quicker conversion of liquid water into its gaseous state.
- Surface area: A larger surface area gives more space for the water particles to evaporate and further allow more direct heat on the surface
- Humidity: Evaporation occurs more slowly in high humidity because there is already a lot of water vapor in the surrounding air.
how is attraction between particles affected when a substance is heated
As a substance is heated, particles gain more kinetic energy causing them to move and vibrate. These small movement competes with the attraction between particles and causes them to move slightly further apart. The bind between particles gradually weakens and is eventually broken.
What is a monotomic ion
A charged particle that consist of only one atom
What are the peoperties of monatomic structures
Individual atoms with very weak forces between them. They have no bonds.
Lowest melting and boiling points; weak bonds. Monatomic elements can’t conduct electricity. Not soluble
What is an isotope
Same element with the same number of protons but different numbers of neutrons and therefore, different atomic masses/ mass numbers
How are molecules formed
When two or more atoms are covalently bonded together
What are non bonding electrons
Electrons on the outer shell which are not involved in the covalent bond
How is a single covalent bond represented
A shared pair of electrons or a singular line
How are the properties of a molecule with double covalent bond different to a molecule with a singular covalent bond?
The bond is stringer and shorter than a singular bond, making it more difficult to overcome the bond.
Why do small molecules not conduct electricity?
Because all electrons have a fixed position. The molecules therefore have no free flowing electrons to carry the electronic charge.
What is the strength of a diamond
Very strong as the strong covalent bonds between carbon atoms in diamond create a tightly packed and uniform structure, making it difficult for atoms to slide past each other
What is the use of diamond due to its properties
-Cutting tools
-Polishing tools
-Electronics
What is the use of graphite due to its properties
Owing to graphite’s soft aud slippery nature, it is used as a grea a type
of lubricant.
• Due to its high electrical conductivity, graphite is reflected in the making of electrodes for electric furnaces.
• The high melting point of graphite makes it suitable for making crucibles for melting metals.
What is a use of graphene due to its properties
Graphene makes composite materials stronger without making them much heavier so is often used in electronics and construction (eg: solar panels and batteries)
Name 3 ways in which ionic bonds are different to covalent bonds
Only non-metals are present, electrons are shared not transfered, particles are together by the attraction of the nuclei and electrons rather than oppositely charged ions.
What is a crystalinne structure
A large number of atoms covalently bonded together in a 3-dimensional arrangement forming a cystalline structure
Process when solid turns into a liquid
Melting
Process when liquid turns into a gas
Evaporation
Process when gas turns into a liquid
Condensing
Process when liquid turns into a solid
Freezing
Describe an ionic lattice
An ionic lattice is a giant structure made of oppositely charged ions held together by strong electrostatic forces of attraction. It has a regular, repeating pattern and forms crystals with high melting and boiling points due to the strong bonds.
Define a coarse particle
Coarse particles (PM 10 ) have diameters between 1 x 10 -5 m and 2.5 x 10 -6
m. They are often referred to as dust.
Define fine particles
Fine particles (PM 2.5 ) have diameters between 100 and 2500 nm (1 x 10 -7 m
and 2.5 x 10 -6 m).
Define metalloids
a chemical element that exhibits some metal and some nonmetal properties.
Cation
Positive charge
Anion
Negative charge
Define a diatomic molecule
A diatomic molecule consists of two atoms chemically bonded together.
Define a chemical bond
These are bonds between atoms in an element or compound
Name me the 7 covalent structures you need to know
Cl^2
Hcl
H2O
O2
N2
Nh3
Ch4
Why do small molecules have low melting and boiling points
Substances made of small molecules have a low melting and boiling point as they have weak intermolecular forces so they need a small amount of energy to overcome this.
Describe and explain the properties and structure of nanotubes
Hexagonal rings,
very high length to diameter ratios.
Bonded to 3 carbon atoms
Can conduct electricity
High melting and boiling point
Potential uses for buckminster fullerene
Drug delivery,lubricants
What happens if there is stronger forces between particles
Higher melting and boiling points
When do particles gain and lose energy
Gain when they are heated
Lose when they are cooled
Iodine at room temp
Solid
Bromine at room temp
Liquid
Chlorine at room temp
Gas
Flourine at room temp
Gas
Define an ionic compound
Chemical compound formed of ions, held together by strong electrostatic forces.
What is a ion
An atom or molecule with an electric charge due to the loss or gain of electrons.
Value of a pico meter
1x10-12
Value of micro meter
1x10^-6
Symbol for micro meters
µ
Value of tera meter
1x10^12
What are reactants
The starting materials in a chemical reaction
What are products
The new substances produced by a chemical reaction
Advantages of using stick and ball diagram
Useful for illustrating the arrangement of atoms in a 3d space
Disadvantages of the ball and stick diagram
Fails at indicating the movement of electrons
Advantages of using dot and cross diagrams
Useful for illustrating transfer of electrons
Disadvantages of using dot and cross diagrams
Fails to illustrate the 3d arrangements of the atoms and electron shells
Use of simple molecules
Insulators
Why do metal atoms become cations in a metal lattice?
Metal atoms lose electrons to form positive ions (cations).
They do this to achieve a stable electron configuration (like noble gases).
The lost electrons become delocalised, forming a “sea of electrons”.
Strong electrostatic forces between cations and electrons create metallic bonds.
Why are metals ductile
Arranged in layers,that means they can slide over eachother with delocalised electrons keeping it together,this allows the metals to be streched
Effects of alloying a metal
Stronger,improves corrosion resistance,can change colour
What are silver nanoparticles used for
Cleaning surgical equipment,water purification,electronics,antifungal and antiviral
Uses of titanium dioxide nanoparticles
Suncreens,cosmetics,deodorants,food colouring
Cations
Positive ions
Anions
Negative ions
explain, in terms of particles, energy
and temperature of a substance when it is
at the melting point
Particles: The particles in a solid gain enough energy to partially overcome the forces holding them in a fixed position. They start to move more freely but remain close together.
Energy: The energy supplied is used to break some of the strong bonds between the particles instead of increasing their temperature.
Temperature: The temperature remains constant while the substance is melting, even though heat is being added. This is because all the energy is used for breaking bonds rather than increasing kinetic energy.
explain, in terms of particles, energy
and temperature of a substance when it is
at the boiling point
At the Boiling Point (Liquid to Gas)
Particles: The particles in a liquid gain enough energy to completely break free from their bonds and move randomly in all directions.
Energy: The energy supplied is used to break all the remaining attractive forces between the particles, allowing them to escape as a gas.
Temperature: The temperature stays constant during boiling, as all the energy is used for breaking bonds rather than increasing kinetic energy.
Define a double bond
A double bond is a covalent bond where two atoms share two pairs of electrons (four electrons in total).
explain why small molecules and
polymers do not conduct electricity.
Small molecules and polymers do not conduct electricity because they do not have free-moving electrons or ions to carry charge. Their covalent bonds hold atoms together, but there are no delocalized electrons like in metals or free-moving ions like in ionic solutions.
explain the movement of ions in
solutions or when molten. In ionic compounds
When ionic compounds are dissolved in water or melted, the ions become free to move.
The positive ions (cations) move towards the negative electrode (cathode), and the negative ions (anions) move towards the positive electrode (anode).
This movement of ions allows the compound to conduct electricity.
explain in detail why ionic compounds cannot conduct electricity when they are solid but can when molten or in solution.
Solid State:
Ions are arranged in a fixed lattice and are held in place by strong electrostatic forces.
Ions cannot move in the solid state, so there are no free-moving charged particles.
Cannot conduct electricity because no particles are available to carry the charge.
Molten or in Solution:
In the molten state or when dissolved, the ionic compound melts or dissociates, and the ions become free to move.
Can conduct electricity because the free-moving positive ions (cations) move towards the negative electrode, and negative ions (anions) move towards the positive electrode. This movement allows the compound to carry an electrical current.
Define a triple bond
A triple bond is a covalent bond in which two atoms share three pairs of electrons (six electrons in total).
suggest how the properties of a double bond could be different to the properties of a single covalent bond.
Double bonds are much stronger then single bonds and having a greater electrostatic forces of attraction.But it is shorter due to the greater force and the two atoms are much closer together.
Define the ionic model
The ionic model is a way of describing the structure and bonding in ionic compounds, where atoms transfer electrons to form ions
Define ball and stick model
The ball-and-stick model is a way of representing molecules where balls represent atoms and sticks represent the bonds between them.
Describe how with a particle size decrease we get a increase in surface area to volume ratio
As particle size reduces, the surface area to volume ratio increases. Here’s how this happens:
Surface Area: The surface area is the outer area of the particle. When you make a particle smaller, you expose more of its surface relative to its overall size.
Volume: The volume is the space inside the particle. As the particle gets smaller, the volume doesn’t decrease as quickly as the surface area.
Graphene
Single layer
Graphite
3 layers
Uses of monatomic elements
Helium,neon,argon
Define small molecules
Small molecules are made up of a few atoms covalently bonded together. These molecules can consist of the same or different types of atoms.
Exam question balanced equation
Fe02
