Unit 3 - Topic 1 - Metals Flashcards
Do metals have a high or low density and why?
Metals have a high density indicating the metal atoms are closely packed together.
Except group 1
Describe metallic bonding
The outer electron(s) on each atom are free to move between the atoms. This results in a regular arrangement (a LATTICE) of POSITIVE IONS with NEGATIVE ELECTRONS moving between the positive ions.
Why are atoms in a metal said to be delocalised?
They are not located on a specific atom.
Describe metal attraction
The electrostatic attraction between the positive ions and the delocalised electrons acts in all 3-dimensions, strongly holding the lattice together.
Do metals have high or low melting and boiling points?
High
Is metallic bonding strong or weak and why?
There is usually a large difference between the melting and boiling point of a metal (its liquid range). This indicates metallic bonding is very strong.
Are metals bad or good conductors of heat and electricity and why?
Good. This is due to the presence of the delocalised electrons.
The movement of the delocalised electrons passes on the energy during conduction of heat.
Describe the conduction of metals
During conduction of an electric current, electrons pushed into the metal from the NEGATIVE ELECTRODE of a battery or power supply make the delocalised electrons move towards the POSITIVE ELECTRODE.
The metal is not affected by the passage of an electric current, as the number of electrons always equals the number of protons in the lattice.
How is metal reactivity measured?
The amount of energy given out when a metal reacts gives a measure of its reactivity.
Describe metals and oxygen
All metals react with oxygen to make a METAL OXIDE.
Potassium permanganate (KMnO4) gives off oxygen when heated.
Different metals can be reacted with pure oxygen to observe how well the react.
Describe an oxidation reaction
A reaction where a reactant loses an electron (or electrons) is called an OXIDATION REACTION.
When metals react their atoms lose electrons to form their ions. This means all metals undergo an OXIDATION REACTION when they react.
Describe metals and acids
When a metal reacts with an acid the products are a SALT and HYDROGEN.
The speed of production of hydrogen gives a measure of the reactivity of the metal.
Describe metals and water
When a metal reacts with water the products are a METAL HYDROXIDE solution (an alkali) and HYDROGEN.
Only metals from groups I (ALKALI METALS), and group II (ALKALINE EARTH METALS), react with water.
Which metals don’t react
Silver (Ag)
Gold (Au)
Which metals react with oxygen
Potassium (K) Sodium (Na) Lithium (Li) Calcium (Ca) Magnesium (Mg) Aluminium (Al) Zinc (Zn) Iron (Fe) Tin (Sn) Lead (Pb) Copper (Cu) Mercury (Hg)
Which metals react with acid
Potassium (K) Sodium (Na) Lithium (Li) Calcium (Ca) Magnesium (Mg) Aluminium (Al) Zinc (Zn) Iron (Fe) Tin (Sn) Lead (Pb)
Which metals react with water
Potassium (K) Sodium (Na) Lithium (Li) Calcium (Ca) Magnesium (Mg)
Describe MAZIT metals
The metals in the middle of the reactivity series are called the MAZIT metals.
They are the most commonly/often used metals
Describe MAZIT
Magnesium (Mg) Aluminium (Al) Zinc (Zn) Iron (Fe) Tin (Sn)
Describe oxidation
When a metal reacts, the metal atoms lose electrons and change into metal ions. This is an OXIDATION REACTION.
The electrons lost from a metal atom during a reaction have to be GAINED by another reactant.
Describe reduction
When a metal reacts, the metal atoms lose electrons and change into metal ions. This is an OXIDATION REACTION.
The electrons lost from a metal atom during a reaction have to be GAINED by another reactant.
Where are the metals we use obtained from?
The Earth’s Crust
Describe obtaining metals
Most metals are too reactive to exist in a pure uncombined form in the Earth’s crust. Metals are found in rocks as metal compounds. The usual metal compounds found in rocks are OXIDES, SULPHIDES and CARBONATES.
Describe native metals
A few metals are found uncombined, as they are very unreactive. Metals, which are found uncombined, are called NATIVE METALS.
Name the native metals
Gold (Au)
Platinum (Pt)
Silver (Ag)
Copper (Cu)
Describe metal ores
Rocks, which contain metals or compounds of metals, are called ORES.
What’s the link between reactivity and date of discovery?
The least reactive metals were discovered the earliest.
Describe metal oxides
A large number of ores contain metal oxides.
To extract a metal from an ore requires heat. Some metal oxides break down by heat alone.
Describe heating Silver (I) Oxide
Silver(I) oxide breaks down on heating to form silver and oxygen.
Silver(I) oxide decomposes on heating to form silver and oxygen.
Describe heating Copper (II) Oxide
Heating has no effect on copper(II) oxide.
Describe a decomposition reaction
Breaking down a compound into its elements from which it is made is called a DECOMPOSITION REACTION.
Describe metal oxides with carbon
Metals with very low reactivity can be extracted by just heating their compounds.
Copper is too reactive to be extracted by HEAT ALONE.
Metals with low to middle reactivity can be extracted by heating their compounds with carbon.
Describe carbon reduction
Zinc (Zn), Iron (Fe), Tin (Sn), Lead (Pb) and Copper (Cu) are extracted using carbon or carbon monoxide. This method of extraction is called carbon reduction.
Describe the results after heating Copper (II) Oxide with Carbon
After the reaction some orange / brown copper can be seen in the beaker.
The products of the reaction are COPPER and CARBON DIOXIDE
Carbon helps remove the oxygen from the copper(II) oxide. The oxygen transfers to the carbon forming carbon dioxide.
Describe the extraction of aluminium
Aluminium is too reactive to extract by heating with carbon or carbon monoxide.
All reactive metals from aluminium upwards on the reactivity series are extracted using ELECTROLYSIS.
Describe alumina
The bauxite ore is purified to produce pure aluminium oxide Al2O3.
Alumina is dissolved in molten cryolite (Na3AlF6), as it has a lower melting point than aluminium oxide, which reduces the energy needed for the extraction.
This solution is electrolysed and molten aluminium metal forms at the negative electrode.
Which metals can be extracted by heat alone or found uncombined (LR-MR)?
Platinum
Gold
Silver
Which metals can be extracted by heat with carbon (LR-MR)?
Copper Lead Tin Iron Zinc
Which metals can be extracted by electrolysis (LR-MR)?
Aluminium Magnesium Calcium Lithium Sodium Potassium
