Chemical Bonding: Metallic Bonding Flashcards
what is metallic bonding?
attraction between the ‘sea of delocalised electrons’ and the positive ions
which groups are involved?
occurs between metals (group 1,2,3 and transition metals)
how does it work?
the metal loses its outer shell electron(s) to form the positive metal ion
electrons are delocalised into the space between the positive metal ions - this is the ‘sea of delocalised electrons’
delocalised electrons are free to move
can metallicly bonded substances conduct electricity and heat? why?
yes
delocalised electrons are free to move
what is an alloy?
mixture of metals (two or more)
what are some examples of alloys?
brass = copper and zinc
steel = iron, zinc and carbon
how can metals be made harder?
by alloying them
(this is the main purpose of alloys)
are atoms in alloys different sizes or the same?
different
what happens as a result of atoms in alloys being different sizes?
this disrupts regular packaging
makes it difficult for particles to slide over each other when a force is applies
what are some uses of copper?
sauce pans
water pipes
electrical wires
door handles
power lines
what are some examples of alloys’ uses?
coins
furniture
car wheels
ships
buildings
what structure do metallic bonds form?
giant metallic structure
what is the giant metallic structure
Regular array of positive ions and ‘sea of delocalised electrons’
held together by the attraction between the two
do metals tend to be strong or weak? high or low melting and boiling points?
why?
strong
high
because of the powerful attractions between them
are metals good or bad conductors of electricity? why?
good
because the delocalised electrons are free to move through the structure
are metals good or bad conductors of heat? why?
good
because delocalised electrons are free to move
if you heat one piece of metal, the energy is picked up by the electrons
as they electrons move, the heat energy is transferred throughout the structure
how do metals conduct electricity?
which metal is used as a coating to prevent rusting and which property does the use depend?
zinc
more reactive than object it is covering
which metal is used as an aircraft body and which property does the use depend?
aluminium
to be strong
which metal is used as electrical wiring and which property does the use depend?
copper
to be bent into shape easily
conducts electricity
sacrificaial protection
which metal is used as railway tracks and which property does the use depend?
steel
ability to expand
very strong
what are some metals described as being? what does this mean?
elastic
this is when, if it is subject to a small force, it will stretch and then return back to its original shape when the force is released
if a large force is applied, the particles slide over each other and stay in their new positions
are metals usually bent into shape easily or with difficulty? why?
easily
because their layers slide easily over each other
what does malleable mean?
easily beaten into shape
what does ductile mean?
easily pulled into wires
