Chemistry- Structure and Bonding Flashcards
Electrons always occupy …. .
shells
The lowest energy levels (those closest to the nucleus) are always filled ….. .
first
1st Shell:
2nd Shell:
3rd Shell:
2,8,8
A substance which contains only one sort of atom is called an
element
The atomic particle with a positive charge is the ……. .
proton
The atomic particle with a negative charge is the ……. .
electron
The atomic particle with no charge is the …….. .
neutron
The part of an atom in which ……… are found is the nucleus.
protons
……… have no overall electrical charge.
Atoms
In a …………. ………, the number of electrons is equal to the number of protons.
neutral atom
Each ……… in an atom is at a particular energy level (in a particular shell).
electron
The atomic particle with a negligible mass is the ………. .
electron
The simplest atom is the ………… atom which contains one proton and one electron.
hydrogen
Neutrons are found in part of the atom called the ……. .
nucleus
All atoms of a particular element have the same number of …….. in their nuclei.
protons
The mass number of carbon is ….
12
The proton number of carbon is …..
6
The number of protons in one atom of fluorine is …..
9
The mass number of fluorine is ……
19
The number of protons in one atom of sodium is …..
11
Why do atoms react?
Most atoms ‘want’ to react. This is why so many compounds exist.
Atoms want to gain a full outer shell of electrons (this is the most stable arrangement of electrons).
Therefore all atoms (apart from the noble gases) want to react and achieve a full outer electron shell.
How do atoms react?
Only the outer shell electrons take part in reactions.
Atoms tend to react by transferring or sharing electrons in order to obtain a full outer shell.
Melting/ boiling points of ionic compounds:
The strong electrostatic attractions in the lattice mean that……….
ionic compounds have very high melting and boiling points.
How can ionic compounds conduct electricity?
As solids, ionic compounds cannot conduct electricity because their ions are bonded together in the lattice.
When molten (melted to a liquid), the ions break away from the lattice are free to move. The ions are chafed particles and can conduct electricity.
Many ionic compounds are soluble and form a solution.
When dissolved, the ions are free to move and can conduct electricity.
When the compound is hit- the layer of ions are dislodged so they match and …… and therefore …….
repel
shatter
When non-metal atoms join together they form …… ……. .
covalent bonds
In covalent bonding, the atoms are wanting to obtain .. ….. ….. … … …….
a full outer shell of electrons
Two (or more) non-metal atoms can gain electrons by ………
sharing
If their outer shells overlap, they share some of each others …..
electrons
metal + non- metal
ionic
non-metal + non-metal
covalent
Substances formed from covalent bonds can be classified into two groups. What are they?
Simple molecular structures (simple covalent)
Giant covalent Structures
oxygen, water and carbon dioxide are ……
molecules
They have a simple molecular structure because they only contain a few….
atoms
Most molecular substances are … .. …….. at room temperature
gas or liquid
They have low ………. …. …….. points.
melting and boiling
A few are solids with fairly low melting points , give an example
iodine
When water boils, it is the weak …….. ………… that break. The strong covalent bonds remain intact.
inter molecular
Explain why methane is a gas at room temperature and water is a liquid.
Methane is a gas at room temperature because it has very weak inter molecular bonds; weaker than water.
Why do they not conduct electricity?
Simple molecular structures have no free electrons (they are shared in covalent bonds and not free to move) and they have no ions.
No free electrons, no ions, therefore cannot conduct electricity.
In some substances, millions of atoms join together by
covalent bonding.
This produces giant covalent structures, not
molecules
All the bonds are covalent, which means that giant covalent structures have a very high …… ….. ……… ……., and are usually hard.
melting and boiling point
In the element carbon, atoms bond in different ways, creating different kinds of giant structures.
Three of these structures are diamond, graphite and buckminsterfullerene. They are called
allotropes of carbon.
What are the properties of Diamond?
The hardest natural material known.
Very high melting point
Does not conduct electricity
Structure of Diamond?
It is a giant covalent structure
It has very strong covalent bonds
In Diamond, each carbon atom is surrounded by 4 other carbon atoms
It requires a lot of energy to break the bonds.
It does not conduct electricity because all of the electrons are in covalent bonds. NO FREE ELECTRONS
What are the properties of Graphite?
Soft and slippery
conducts electricity
high melting point
Structure of Graphite?
Has a layered structure
Bonds in the layers are strong covalent bonds
Each carbon atom is surrounded/ bonded by 3 carbon atoms
There is a weka inter-molecular bond between the layers. This means they can slide.
It can conduct electricity because there is a free electron between the layers.
Info on Buckyball (3 points)
It is also called C60
It is ‘just’ considered giant
It is used as a lubricant and can deliver drugs into the body.
Other allotropes of carbon
Graphene, Carbon nanotubes
Info on sand (3 points)
Sand is an impure form of silicon dioxide (quartz). It has a giant covalent structure with certain similarities to diamond.
Each silicon is bonded covalently to 4 oxygen atoms.
Sand has a very high melting point.
Explain why it is possible to bend a piece of metal-
The layers off atoms can move easily allowing the piece of metal to bend.
There are delocalised/ free electrons
Move/slide
Attraction when bend metal
An alloy is…
a mixture of a metal with at least one other element.
Steels are alloys of iron with…
carbon and/or other elements.
Why is steel stronger than iron?
The atoms in pure iron are arranged in densely packed layers. these layers ca slide over each other. This makes pure iron a very soft material. The atoms of other elements are different sizes. When other elements are added to iron, their atoms distort the regular structure of the iron atoms.
It is more difficult for the layers of iron atoms in steel to slide over each other and so this alloy is stronger than pure iron.
What’s so clever about smart alloys?
Shape memory alloys or smart alloys are metals that return to their original shape after being deformed. Shape memory alloys can be used in medicine and dentistry. For example, nitnol, made from nickel and titanium, is used in dental braces.
Metals are found in the…
Earth’s crust
We find most metals combined chemically with other chemical elements, often with…
oxygen or sulphur
This means that the metal must be ….. …… from its compounds before it can be used.
chemically separated
What is metal ore?
Metal Ore: enough metal (or compound) in a rock to make it worth extracting the metal. Ores are mined from the ground.
Gold and silver are so un reactive that they are found in Earth as ….
the metals (elements) themselves.
The way that we extract a metal depends on…
its place in the reactivity series.
A more reactive metal will displace a..
less reactive metal.
What is the reactivity series? P S C M A C Z I T L C S G P
Potassium (extracting using electrolysis) Sodium Calcium Magnesium Aluminium
Carbon
Zinc (extracted using carbon in a blast furnace) Iron Tin Lead Copper
Silver (found native, no extraction required)
Gold
Platinum
We can find many metals, such as copper, lead, iron and zinc, combined with oxygen as metal oxides. Because carbon is more reactive than each of these metals, we can use carbon….
to extract the metals from their oxides.
The removal of oxygen fro a compound is called …
chemical reduction.
Iron is a ………. reactive metal.
Iron ore is plentiful and relatively easy to reduce to iron metal.
Iron ore is reduced by heating with carbon in a ………. ………… .
It is cheap, strong and malleable.
Iron is the most ………. used metal.
moderately
Blast Furnace
commonly
What happens (in order) in the Blast Furnace?
Raw materials are added to the furnace.
Carbon Dioxide reacts with coke to form carbon monoxide.
Hot air added.
Carbon rich coke is burnt in oxygen.
Carbon Dioxide is formed.
Iron oxide in the iron ore is reduced by the carbon monoxide to form iron.
Molten iron produced collects in furnace.
Limestone reacts with impurities to form slag which is drained.
Carbon Dioxide and Nitrogen are released as waste gases.
carbon burns with oxygen to form
carbon dioxide
carbon dioxide reacts with more carbon to form
carbon monoxide
carbon monoxide reduces the iron oxide to form
iron
Calcium Carbonate decomposes to form
calcium oxide
Calcium oxide reacts with silicon dioxide to form
calcium silicate (slag)
What type of reaction produces iron?
Reduction
Explain why recycling iron is necessary for sustainable development.
decreasing waste materials
reserves materials/ ore
decreases - global warming
- carbon dioxide
