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what is an ion?
a charged particle formed by the gain or loss of electrons
all metals ____ electrons to become _____ly charged ions
lose, positive
all non metals ____ electrons to become ____ly charged ions
gain, negative
what is ionic bonding?
transfer of electrons from a metal to a non metal to form a positively charged metal ion and a negatively charged non metal ion
what holds ionic compounds together?
the positive and negative charges are held together by the strong electrostatic forces of attraction that act in all directions
what are the structures of ionic compounds?
they are composed of 100s of ions both positive and negative, held together by strong electrostatic forces, this forms 3D structures called a giant lattice structure
how can ionic compounds be represented?
using a ball and stick diagram
what are the properties of ionic compounds?
- can only conduct electricity when melted or dissolved in water as the ions are free to move/ flow and are no longer fixed
- very high melting point as lots of energy is needed to overcome the electrostatic forces of attraction
how does metallic bonding work?
each metal atom donates its outer electron to become a positively charged ion and these electrons are free to move creating a sea of electrons. The metallic bond is the electrostatic force of attraction between these positive metal ions and the negative electrons. This holds the metal together in a regular lattice structure
what are alloys?
a mixture of two or more elements containing at least one metal
why are alloys stronger than regular metals?
the different sized atoms disrupt the regular structure/causes distorted layers so the layers can no longer slide over each other so it’s stronger
why do metals with a greater number of outer electrons have a higher melting point?
This is due to the increased positive charge on the metal ion and the increased number of electrons that are delocalised, resulting in stronger bonding.
how do metals conduct electricity
their outer electrons of each metal atom are delocalised so they are free to flow within the structure and carry charge
what is covalent bonding?
a shared pair of electrons between two non metal atoms
what are polymers?
long chains made up of large repeating units called monomers
are polymers solid at room temperature?
yes as the molecules are really big, so the intermolecular forces add up to be quite strong, however most polymers melt easily as the intermolecular forces remain less strong than the chemical bonds
do covalent structures conduct electricity? explain your answer
no as they have no free electrons and they don’t have any charged particles( except graphite)
why do simple covalent structures have a low melting point?
because they have small molecules causing them to have weak intermolecular forces so little energy is needed to overcome these
do giant covalent structures have intermolecular forces?
no as it’s just one giant molecule
why do giant covalent structures have high melting points?
because it takes a lot of energy to break all the strong covalent bonds between the atoms in the structure
what are allotropes?
different structural forms of the same element in the same physical state
what are the allotropes of carbon?
- diamond
- graphite
- graphene
- buckminsterfullerene
what is the structure of diamond?
each carbon atom is covalently bonded to 4 other carbon atoms
what are the properties of diamond?
- can’t conduct electricity as it has no free electrons or ions
- high melting point
- strong
what is the structure of graphite?
each carbon atom is covalently bonded to three others, the atoms are arranged in hexagons that form flat sheets that form layers on top of each other
what are the properties of graphite?
- slippery
- can conduct electricity
- high melting point
why is graphite slippery?
they have layers that are held together by weak intermolecular forces as there are no covalent bonds between them so they can slide over each other making graphite soft and be used in pencil lead
why can graphite conduct electricity?
because each carbon atom is only bonded to three others, and carbon can make 4 covalent bonds, so there’s a carbon atom that isn’t bonded, so there’s a delocalised electron that is free to flow and carry charge through the structure and conduct electricity
what is graphene?
a singular layer of graphite
how are fullerenes such as nanotubes made?
made by bending sheets of graphene
what are fullerenes?
molecules of carbon with hollow shapes
what is buckminsterfullerene?
C60 first fullerene to be discovered, spherical
uses of fullerenes
- industrial catalysts (spherical)
- transporting drugs into the body (spherical)
- electronics (cylindrical)
- strengthening materials eg. in tennis rackets
- lubricants (spherical)
what are the uses of nanoparticles
- silver nanoparticles have antibacterial properties so we can infuse them into surgical masks and wound dressings as they are lightweight as well
- catalysts due to their high surface area: volume ratio
- conducting electricity
- deodrants
- sunscreens
what are the issues with using nanoparticles
- the use of nanoparticles is in ealry stages so we don’t know its long term effects on the human body ( if used in sunscreams for example)
- we don’t know if they damage the environment when they’re disposed of
- they aren’t easily disposed of
what are the advantages of a dot and cross diagram?
- useful for illustrating the transfer of electrons
- indicates from which atom the bonding electrons come from
what are the disadvantages of a dot and cross diagram?
- doesn’t indicate the relative sizes of atoms
- doesn’t illustrate the 3D arrangements of the atoms and electron shells
what are the advantages of a ball and stick model?
- useful for illustrating the arrangement of atoms in 3D space
- useful for visualizing the shape of a molecule
what are the disadvantages of a ball and stick model?
- doesn’t show movement of electrons
- gives no information about the forces of attraction between the ions
- the atoms are placed far apart from each other, which in reality is not the case as the gaps between the atoms are much smaller
what are the advantages of 2D models?
- , shows what atoms are in a molecule and how they’re connected
- simpler versions of the ball and stick model
what are the disadvantages of 2D models?
- fails to illustrate the relative sizes of the atoms and bonds
- can’t give you an idea of the shape of a molecule and what it looks like in 3D space
describe the structure of a solid
strong forces of attraction holds the particles close together to form a regular lattice structure
definite shape and volume
can’t be compressed
strong forces of attraction
what happens when a solid is heated
particles gain kinetic energy and vibrate more weakening the bonds between them until the melting point is reached and the particles gain enough energy to break free of their bonds
—>liquid
describe the structure of a liquid
free to move
shape can flow to fit a container
definite volume
weak forces of attraction
what happens when a liquid is heated
the particles gain more kinetic energy and move around faster/vibrate and slide over each other weakening the forces between them until boiling point is reached and the bonds are broken and the liquid evaporates into a gas
describe the strucuture of a gas
free to move
no definite shape or volume
very weak forces of attraction
constantly move with random motion
what happens when a gas is heated
if it’s in an expandable container the gas will expand
if it’s in a fixed container the pressure will increase
what happens when a gas is cooled down
won’t have enough energy to overcome bonds as energy is transferred to the surroundings so bonds will form again and it will condense into a liquid
what happens when a liquid cools down
energy from the liquid is transferred to the surroundings and so it won’t have enough energy to overcome the forces of attraction between the bonds/particles and it will freeze into a solid fixing the particles in place
what are the limitations of the particle model
particles aren’t solid since atoms are mostly empty space
many particles aren’t spherical
what is an ion?
a charged particle formed by the gain or loss of electrons
all metals ____ electrons to become _____ly charged ions
lose, positive
all non metals ____ electrons to become ____ly charged ions
gain, negative
what is ionic bonding?
transfer of electrons from a metal to a non metal to form a positively charged metal ion and a negatively charged non metal ion
what holds ionic compounds together?
the positive and negative charges are held together by the strong electrostatic forces of attraction that act in all directions
what are the structures of ionic compounds?
they are composed of 100s of ions both positive and negative, held together by strong electrostatic forces, this forms 3D structures called a giant lattice structure
how can ionic compounds be represented?
using a ball and stick diagram
what are the properties of ionic compounds?
- can only conduct electricity when melted or dissolved in water as the ions are free to move/ flow and are no longer fixed
- very high melting point as lots of energy is needed to overcome the electrostatic forces of attraction
how does metallic bonding work?
each metal atom donates its outer electron to become a positively charged ion and these electrons are free to move creating a sea of electrons. The metallic bond is the electrostatic force of attraction between these positive metal ions and the negative electrons. This holds the metal together in a regular lattice structure
what are alloys?
a mixture of two or more elements containing at least one metal
why are alloys stronger than regular metals?
the different sized atoms disrupt the regular structure/causes distorted layers so the layers can no longer slide over each other so it’s stronger
why do metals with a greater number of outer electrons have a higher melting point?
This is due to the increased positive charge on the metal ion and the increased number of electrons that are delocalised, resulting in stronger bonding.
how do metals conduct electricity
their outer electrons of each metal atom are delocalised so they are free to flow within the structure and carry charge
what is covalent bonding?
a shared pair of electrons between two non metal atoms
what are polymers?
long chains made up of large repeating units called monomers
are polymers solid at room temperature?
yes as the molecules are really big, so the intermolecular forces add up to be quite strong, however most polymers melt easily as the intermolecular forces remain less strong than the chemical bonds
do covalent structures conduct electricity? explain your answer
no as they have no free electrons and they don’t have any charged particles( except graphite)
why do simple covalent structures have a low melting point?
because they have small molecules causing them to have weak intermolecular forces so little energy is needed to overcome these
do giant covalent structures have intermolecular forces?
no as it’s just one giant molecule
why do giant covalent structures have high melting points?
because it takes a lot of energy to break all the strong covalent bonds between the atoms in the structure
what are allotropes?
different structural forms of the same element in the same physical state
what are the allotropes of carbon?
- diamond
- graphite
- graphene
- buckminsterfullerene
what is the structure of diamond?
each carbon atom is covalently bonded to 4 other carbon atoms
what are the properties of diamond?
- can’t conduct electricity as it has no free electrons or ions
- high melting point
- strong
what is the structure of graphite?
each carbon atom is covalently bonded to three others, the atoms are arranged in hexagons that form flat sheets that form layers on top of each other
what are the properties of graphite?
- slippery
- can conduct electricity
- high melting point
why is graphite slippery?
they have layers that are held together by weak intermolecular forces as there are no covalent bonds between them so they can slide over each other making graphite soft and be used in pencil lead
why can graphite conduct electricity?
because each carbon atom is only bonded to three others, and carbon can make 4 covalent bonds, so there’s a carbon atom that isn’t bonded, so there’s a delocalised electron that is free to flow and carry charge through the structure and conduct electricity
what is graphene?
a singular layer of graphite
how are fullerenes such as nanotubes made?
made by bending sheets of graphene
what are fullerenes?
molecules of carbon with hollow shapes
what is buckminsterfullerene?
C60 first fullerene to be discovered, spherical
uses of fullerenes
- industrial catalysts (spherical)
- transporting drugs into the body (spherical)
- electronics (cylindrical)
- strengthening materials eg. in tennis rackets
- lubricants (spherical)
what are the uses of nanoparticles
- silver nanoparticles have antibacterial properties so we can infuse them into surgical masks and wound dressings as they are lightweight as well
- catalysts due to their high surface area: volume ratio
- conducting electricity
- deodrants
- sunscreens
what are the issues with using nanoparticles
- the use of nanoparticles is in ealry stages so we don’t know its long term effects on the human body ( if used in sunscreams for example)
- we don’t know if they damage the environment when they’re disposed of
- they aren’t easily disposed of
what are the advantages of a dot and cross diagram?
- useful for illustrating the transfer of electrons
- indicates from which atom the bonding electrons come from
what are the disadvantages of a dot and cross diagram?
- doesn’t indicate the relative sizes of atoms
- doesn’t illustrate the 3D arrangements of the atoms and electron shells
what are the advantages of a ball and stick model?
- useful for illustrating the arrangement of atoms in 3D space
- useful for visualizing the shape of a molecule
what are the disadvantages of a ball and stick model?
- doesn’t show movement of electrons
- gives no information about the forces of attraction between the ions
- the atoms are placed far apart from each other, which in reality is not the case as the gaps between the atoms are much smaller
what are the advantages of 2D models?
- , shows what atoms are in a molecule and how they’re connected
- simpler versions of the ball and stick model
what are the disadvantages of 2D models?
- fails to illustrate the relative sizes of the atoms and bonds
- can’t give you an idea of the shape of a molecule and what it looks like in 3D space
describe the structure of a solid
strong forces of attraction holds the particles close together to form a regular lattice structure
definite shape and volume
can’t be compressed
strong forces of attraction
what happens when a solid is heated
particles gain kinetic energy and vibrate more weakening the bonds between them until the melting point is reached and the particles gain enough energy to break free of their bonds
—>liquid
describe the structure of a liquid
free to move
shape can flow to fit a container
definite volume
weak forces of attraction
what happens when a liquid is heated
the particles gain more kinetic energy and move around faster/vibrate and slide over each other weakening the forces between them until boiling point is reached and the bonds are broken and the liquid evaporates into a gas
describe the strucuture of a gas
free to move
no definite shape or volume
very weak forces of attraction
constantly move with random motion
what happens when a gas is heated
if it’s in an expandable container the gas will expand
if it’s in a fixed container the pressure will increase
what happens when a gas is cooled down
won’t have enough energy to overcome bonds as energy is transferred to the surroundings so bonds will form again and it will condense into a liquid
what happens when a liquid cools down
energy from the liquid is transferred to the surroundings and so it won’t have enough energy to overcome the forces of attraction between the bonds/particles and it will freeze into a solid fixing the particles in place
what are the limitations of the particle model
particles aren’t solid since atoms are mostly empty space
many particles aren’t spherical