Topic 8 - Metals Flashcards
(25 cards)
What is metallic bonding?
the electrostatic force of attraction between positively charged ions and
delocalised electrons.
Why do metallic elements conduct electricity?
because they contain delocalised electrons
Metal + oxygen
metal oxide
Metal + water
metal hydroxide + hydrogen
metal + dilute acid
salt + hydrogen
How can metals be arranged in order of reactivity?
By comparing the rates at which they react with substances such as acids or water.
How are soluble salts produced using metals?
Excess metal is added to the appropriate acid. The mixture is filtered to remove unreacted metal, and the filtrate is evaporated to dryness to obtain the salt.
What is reduction?
a gain of electrons by a reactant in any reaction
What is oxidation?
a loss of electrons by a reactant in any reaction
What happens in a redox reaction
reduction and oxidation take place at the same time
What happens during the extraction of metals?
metal ions are reduced forming metal atoms
The method used to extract a metal from its ore depends on
the position of the metal in the
reactivity series.
What are the methods used to extract metals?
- heat alone (for extraction of Ag, Au and Hg)
- heating with carbon or carbon monoxide (for extraction of Cu, Pb, Sn, Fe and Zn)
- electrolysis (for extraction of more reactive metals including aluminium)
What is electrolysis
the decomposition of an ionic compound into its elements using electricity
What supply must be used if the products of electrolysis are to be identified?
d.c
What happens to positive and negative ions in electrolysis?
Positive ions gain electrons at the negative electrode and negative ions lose electrons at the positive electrode.
What are electrolytes?
electrically conducting solutions containing ions
How can a simple cell be made
by placing two metals in an electrolyte
How can another type of cell be made?
using two half-cells (metals in solutions of their own ions).
What is a ‘ion bridge’ (salt bridge) used for
it is used to link the half-cells. Ions can move across the bridge to complete an electrical circuit.
Electricity can be produced in cells where
at least one of the half-cells does not involve metal atoms/ions.
What material can be used as an electrode in non-metal half-cells?
a graphite rod
Different pairs of metals produce
different voltages. These voltages can be used to arrange the elements into an electrochemical series.
The further apart elements are in the electrochemical series
the greater the voltage produced when they are used to make an electrochemical cell
