C2 Bonding, Structures and Properties Flashcards
what does ionic bonding occur with?
metals + non-metals
what will the electrons go from in ionic bonding?
metal to non-metals
how does an ionic bond from between sodium and chlorine?
The sodium atom (transfers) loses one electron to the chlorine atom to form a sodium ion.
The chlorine atom gains one electron from the sodium atom to form a chlorine ion.
The electrostatic force of attraction between the atoms are reasonably stronger which forms an ionic bond
what are the 3 properties of ionic substances?
- high melting and boiling points
- conducts electricity when molten and dissolved
- usually soluble in water (inorganic solvent)
why do ionic substances have high melting and boiling points?
they have strong forces of attraction between oppositely charged ions, these require a lot of energy to break
why do ionic substances conduct electricity?
charged ions are free to move and carry electrical charge
why are ionic substances usually soluble in water?
water has a positive and negative end so ionic ions attract and dissolve
what can the formula of ionic substances tell us?
the ratio of __ ions to __ ions
what does the formula Al2O3 tell us?
the ratio of Al3+ ions to O2+ ions in aluminium oxide is 2:3
what does covalent bonding happen between?
non-metal + non-metals
what does covalent bonding happen between?
non-metal + non-metals
what does covalent bonding involve?
the sharing of electrons
what does covalent bonding involve?
the sharing of electrons
why does covalent bonding happen?
to become stable / have a full outer shell
what are the 3 properties of covalent substances?
- low melting and boiling points
- cannot conduct electricity
- not soluble
why do covalent substances have low melting / boiling points?
have weak intermolecular forces that hold molecules together, when the substance boils these forces are overcome which don’t require much energy (not the strong covalent bonds)
why can’t covalent substances conduct electricity?
they don’t have free moving electrons or ions, molecules are neutral
why are covalent substances not soluble?
they are not charged
define allotrope
different structure of the same element under the same conditions
describe the structure of graphite
Hexagonal layered structure
Carbon atoms covalently bonded to 3 others
1 electron per carbon atom delocalised and free to move through the structure (conducts electricity)
There are weak intermolecular forces of attraction between the layers (brittle + why there are used in pencils)
what are the 2 properties of graphite?
- soft layers that can slide
- conducts electricity
why does graphite have soft layers that can slide?
weak intermolecular forces between layers
why does graphite conduct electricity?
the delocalised electron is free to move through the structure
describe the diamond structure
- tetrahedral structure, each carbon atom is bonded to 4 others
- no free electrons
- very hard
what are the properties of diamond?
- high melting points
- poor conductivity (insulator)
what are the properties of diamond?
- high melting points
- poor conductivity (insulator)
why does diamond have high melting points?
due to many strong covalent bonds in lattice structure
why is diamond a poor conductor?
no free electrons or ions
explain why graphite conducts electricity but diamond does not
Each carbon atom is bonded to 4 carbons in diamond, but only 3 in graphite, the delocalised electron can move through the graphite structure
describe graphene
-Strong covalent bonds between carbons
-3 carbons bonded so delocalised electron
describe Buckminsterfullerene
-Covalently bonded carbon atoms
-Used as drug delivery systems due to space inside
-Bonded together with pentagons and hexagons
Explain why nitrogen is a gas at room temperature. Answer in terms of nitrogen’s structure
Nitrogen is a non-metal which means it has weak intermolecular forces. This is why the atoms are spread apart and don’t touch each other. Very less energy is needed to keep them apart and overcome the force.
what occurs between metallic bonding?
metal + metal
what is metallic bonding?
An electrostatic force of attraction between delocalised electrons and positive metal centres arranged in layers
what can electrons do in metallic bonding?
The electrons are free to move randomly through the structure within the metallic lattice
what are the properties of metallically bonded substances?
- high melting and boiling points
- thermal and electrical conductors
- malleable and ductile
why do metallically bonded substances have high melting and boiling points?
strong electrostatic forces of attraction between delocalised electrons and positive ions is strong throughout the entire lattice
why do metallically bonded substances have thermal and electrical conductors?
delocalised electrons are free to move randomly but when a voltage is applied, the electrons can move through the structure and carry an electrical charge
why is metallically bonded structures malleable and ductile?
the positive centres are arranged in layers that can slide over one another when a force is applied, changing its shape
define nanometre?
a thousand millionth of a metre (1 x 10^-9)
what are nanoparticles used for?
drug delivery, carbon nanotubes and sunscreen
why do nanoparticles have different properties?
they have a very large surface area compared to their volumes
why does silver stop unpleasant smells when wearing socks?
it kills bacteria
how is the size of silver nanoparticles different from normal sized silver particles?
silver nanoparticles are smallER
describe Buckminster fullerene in terms of structure and bonding
- simple molecule
- covalently bonded
describe graphite in terms of structure and bonding
- covalently bonded
- giant covalent
describe graphene in terms of structure and bonding
- ionic bonding
- giant lattice
what are the uses of graphite?
used in pencils, and as an lubricant
why is graphite used a lubricant?
because it has layers that can slide over each other
how do you identify if something is a giant lattice or a simple molecule?
a giant lattice has a fixed composition, a simple molecule can have infinite amounts of bonded atoms
state the relationship between MP/BP and the strength of the forces between particles
- if there is a stronger strength of forces between molecules then it will have a high MP/BP as it requires a lot of energy to overcome
why are pure metals too soft to use?
because they have a regular arrangement of layers
how do you change a pure metal to an alloy?
by adding atoms of a different element that makes the mixture harder
why do pure metals become harder by adding other atoms (process of alloy)?
because there are different size to the pure metal’s atoms. this disturbs the regular arrangement that stops them from sliding over each other
what do ionic bonds usually form?
lattices
what do covalent bonds usually form?
simple molecules
why are alloys harder than pure metals?
(in an alloy) the atoms are of
different sizes
(so) the layers (of atoms in an
alloy) are distorted
(so in an alloy) the layers slide
over each other less easily (than
in a pure metal)
Between Lithium, Magnesium and Aluminium, which metal would form compounds with the highest melting point?
Aluminium has the highest charge (3+), so it will have the strongest ionic bonds and a high melting point.
What is the word for a mixture of two or more elements, where at least one element is a metal?
alloy
What are coarse particles commonly referred to as?
dust particles
In which of the three states of matter do the particles have least energy?
Particles in a solid have the least energy, as they move the least, so have low kinetic energy.
True or false? A polymer is a substance made of macromolecules.
true
What is the name for a large molecule made up of many small units?
macromolecules; Many monomer molecules react to form long chain polymer molecules.
True or false? Simple molecular substances contain delocalised electrons.
false
Fill in the blank in this sentence. Oppositely charged ions in an ionic compound are held together by __________ forces.
electrostatic
