Metallic and ionic bonding Flashcards
a metal atom loses electrons to become a positively charged
cation
a non metal gains electrons to become a negatively charged
anion
what happens when lots of cation and anions form in this way
when large amounts of cations and anions are formed in this way, they arrange themselves into a three dimensional lattice
cross over method
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the _____ ion is placed before the ______ eg MgO
what is the one exception
cation before the anion
sodium ethanoate CH3COONa
the total charged of the cation and anion should be
0 balanced
subscripts
subscripts are used when there are more one ions in a compound
what are polyatomic ions
polyatomic ions are ions that contain more than atom and have an overall charge.
some examples are
Nitrate NO3 -
carbonate CO3 2-
what does the anion end in
ide
for polyatomic anions containing oxygen
they end in -ite or -ate
properties of metals
conductors of electricity and heat malleable ductile high boiling temperatures high densities lustrous low ionisations energies and electroneagtivities
important exceptions of metal properties
mercury is liquid at room temperature
chromium is brittle
group 1 metals are soft
Transition metals
found in the D block
are in the human body in low concentrations
compared to main group metals:
they are harder, have higher densities, higher melting points, some have magnetic properties
the metallic bonding model
the metallic bonding model is a 3D lattic of cations that are surrounded by a sea of delocalised electrons. the lattice is held together by a sea of electrostatic attractions
limitations of the metallic bonding model
cannot explain range of melting temperatures
density variations
different electrical conductivity
metal reactivity with water
metals react violently with water. group 1 metals are more reactive than main group metals. exothermic reaction
metal + water = metal hydroxide + Hydrogen gas
metal reactivity with acids
metal + acid = salt + hydrogen gas
Cu (s) + 2HCl (aq) = CuCl2 (aq) + H2(g)
metal reactivity with oxygen
metal + oxygen = metal oxide
reactivity series of metals
chemists have experimentally made a list of metals that indicate the reactivity of metals
ore
an ore is a natural compound that contains a metal
iron ore is a mineral
extraction of iron from its ore
coke reacts iron = carbon monoxide reacts with iron ore = Iron and slag molten are at the bottom
Fe2O3 = 3CO = 2Fe + 3CO2
environmental, economic issues and social issues with metallic extraction
environmental: pollution, disposal of slag
economic: benefits countries
social issues: land use issues with mining, tourism tourism and farms
metal modification
some metals are used in their pure form - aluminium and copper. other are modified
how metals are be modified
alloying
heat treatment and work hardening
coating
alloying
involes melting and mixing metals together and then cooling them into a solid. alloys are harder, less malleable and poorer electrical conductors
substitutional alloys
made from elements similar in size and chemical properties
interstitial alloys
made from different sized atoms
crystals
regions in a solid in which particles are arranged in a regular way.
the malleability and brittleness is dependent on the size of the crystals and their arrangement
smaller crystals vs larger crystals
smaller crystals are harder, less movement of layers of ions more malleable.
larger crystals more breaks, brittle more gaps
