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Metals all have similar physical properties…
•They have high melting and boiling points (except mercury)
•They conduct electricity and heat.
•They have a high density.
•They are shiny (lustrous).
•They are malleable (can be moulded)
•They are ductile (can be stretched)
Non-metals….
• Have low melting and boiling points.
• Are brittle.
• Do not conduct heat or electricity well.
(except carbon)
Different metals are suitable for different jobs.
Gold, silver and platinum are very unreactive but very malleable - making them suitable for jewellery
Copper is malleable, ductile and it conducts heat and electricity well.
It is also unreactive making it suitable for holding and carrying water.
Aluminium is a reactive metal, but it forms a
coating of very stable aluminium oxide.
This, together with its lightness and malleability gives it many uses from window frames to
insulation foil.
Remember:
Only iron oxide is called rust.
No other metal rusts!Unfortunately iron is quite
brittle (for a metal) and also oxidises (rusts) easily.
As it forms, iron oxide constantly flakes away
exposing more of the iron underneath.
Like aluminium, zinc oxidises to form a stable coating of
zinc oxide which protects the iron underneath it.
This is called galvanising.
To prevent this happening, iron is often covered with a
thin layer of zinc.
Lead is very dense, unreactive and malleable - making it suitable for fishing
weights and roof sealing.
Lead fumes have been linked to brain damage so it is now considered too toxic to be
used inside houses (e.g. as in old-fashioned water pipes)
Back
Sodium, Calcium and Magnesium
These three metals are all far too reactive to be much use in their pure form.
They all make important compounds though.
Sodium
Sodium metal is so reactive it has to be kept in oil to keep it away from the oxygen in the air..
Without the oil, sodium quickly oxides into useless sodium oxide
All the same, sodium is essential for both plants and animals.
The commonest source of sodium is common table salt –
Sodium Chloride.
Calcium
Calcium is less reactive than sodium, but it still oxidises too rapidly for the pure metal to have any uses.
Calcium compounds, however, are very important.
Calcium carbonate makes up about 10% of the earth’s surface – limestone, marble and chalk.
Calcium compounds are essential for life – such as for making bones and milk.
Magnesium
Magnesium is less reactive then sodium or calcium.
It is still too reactive to have any uses in its pure form though.
Magnesium is easily obtainable from salts in sea water
Amongst other things, magnesium is essential for making chlorophyll.
Metals get more reactive as you move left in the periodic table
…. so Group 1 metals are the most reactive
Reactivity
Group 1 metals are the most reactive.
then Group 2
and potassium
is more reactive than sodium
Reactivity
These group 1 metals are too reactive
to be allowed in labs.
On the other hand, its difficult to get copper and zinc to do
anything!
Reactivity
Group 14 elements don’t form ions
This is because they have 4 electrons in their outer shell. It isn’t easier to gain 4 more or lose 4 - so they don’t do either!
Group 18 elements don’t form ions either.
This is because they already have the full 8 electrons in their
outer shell.
Group 1 metals all have one electron in
their outer shell.
They can lose this electron to form a
1+ positive ion
Fr
Cs
Rb
K
Na
Li3
11
19
Ra
Ba
Sr
Ca
Mg
Be4
12
20
Group 2 metals have 2 electrons
in their outer shell….
….. so they form 2+ ions
Ba2+
Sr2+
Ca2+
Mg2+
Be2+
Ra2+
Non-metals can form two types of ion:
Monatomic ions
(the ion is made from just one non-metal element)
Cl - = chloride
I - = iodide
Br - = bromide
O 2- = oxide
S 2- = sulphide
Polyatomic ions
(the ion is made from more than one non-metal element)
OH- = hydroxide
SO42- = sulphate
NO3- = nitrate
CO32- = carbonate
HCO32- = hydrogen carbonate
Metal and non-metals join together to make IONIC compounds.
+ 2CuO2Cu
copper
O2
oxygen copper oxide
Mg + Cl2 MgCl2
magnesium chlorine magnesium chloride
Reactions with Metals.
1. Metals react with oxygen to from oxides.
2. Metals react with water to form hydroxides and hydrogen gas.
3. Metals react with acids to form salts and hydrogen gas.
1. Metals react with oxygen (O2) to form oxides.
sodium + oxygen sodium oxide
4Na O2+ 2Na2O
calcium + oxygen
+
O2
calcium oxide
2Ca 2CaO
oxygen
+
+
3O2
iron iron oxide
4Fe 2Fe2O3
2. Metals react with water to produce hydroxides and hydrogen gas.
sodium + water sodium hydroxide + hydrogen gas
2Na 2H2O+ 2NaOH + H2
calcium + water calcium hydroxide + hydrogen gas
Ca(OH)2Ca 2H2O+ + H2
*Soluble hydroxides are called alkalis*
3. Metals react with acids to form salts and hydrogen gas
potassium + hydrochloric acid potassium chloride + hydrogen
2K + 2HCl 2KCl + H2
++
potassium + sulphuric acid potassium sulphate + hydrogen
2K H2SO4 K2SO4 H2
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