TOPIC 9 - Magic Metals Flashcards
Metallic bonding
As the outer electrons are delocalised; this produces an electrostatic force of attraction between the positively charged metal ions, and the negatively charged delocalised electrons.
How do metallic bonds allow conductivity?
The delocalized electrons are free to move therefore an electrical current can flow (through metallic materials.)
Many transition metals can be used as
catalysts.
Do metals combine to form compounds?
No
What do metals mix to form
alloys.
All metals are
insoluble.
Reaction of metal reacting with water
metal + water -> metal hydroxide + hydrogen
All metals above ______ react with acids
hydrogen
The first _ elements in the EM series react with water
4
All the metals above _____ react with oxygen
gold
Reaction of metal reacting with acid
metal + acid -> salt + hydrogen
Reaction of metal reacting with oxygen
metal + oxygen -> metal oxide
The first metals to be discovered were the most unreactive and remained uncombined, these are:
silver and gold
equation for extraction of metal through heat alone
metal oxide -> metal + oxygen
equation for extraction of metal through heat with carbon or carbon monoxide
metal oxide + carbon -> metal + carbon dioxide
equation for extraction of metal through electrolysis
metal ions -> metal + oxygen
reducing agents; name 4
carbon, carbon monoxide, hydrogen and methane
reducing agents remove ____ from a metal ____.
oxygen; oxide.
ELECTROLYSIS: the positive metal ion is attracted to the ______ electrode where it _____ enough electrons to _______. This is a ______ reaction.
negative; gains; turn back into the metal atom; reduction
ELECTROLYSIS: the non-metal ion is attracted to the ______ electrode where it _____ enough electrons to ________. This is a ______ reaction.
positive; loses; form the element; oxidation
an electrolyte
ionic solution
what does the electrolyte do
complete the circuit
a basic electrochemical cell requires
two different metals connected by an external circuit and between the metals there is an electrolyte
electricity is produced by
the flow of electrons from one metal to the other
redox can also be known as
displacement reactions.
what is a displacement reaction
where a metal ion is displaced from solution by a metal higher up the electromagnetic series
reactions in fuel cells
2H₂ -> 4H⁺ + 4e⁻
O₂ + 4H⁺ + 4e⁻ -> 2H₂O
when metals react with oxygen the process is called
corrosion / rusting for iron
rusting in iron requires:
iron, oxygen and water
a rusting indicator
ferroxyl
ferroxyl goes ___ when iron ions are present
yellow to blue
ferroxyl goes ___ when hydroxide ions are present
yellow to pink
when iron rusts in ferroxyl indicator it goes dark blue because
the blue iron(2+) ions mask the pink hydroxide ones
how to speed up rusting
increasing the concentration of the electrolyte
how to prevent rusting (4)
paint, grease, plastic and metal plating with unreactive metals
sacrificial protection is when
metals higher up in the electrochemical series than iron donate electrons that prevent the iron rusting.
galvanising is when
iron is coated in a layer of zinc, which acts like a barrier against air and water, but if the zinc is damaged it acts like a sacrificial protector to the iron.
what is the only problem with galvanising
expensive
cathodic protection is where
iron is attached the negative terminal of a battery or electrical supply
