Finding and Using Metals

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Finding and Using Metals
The relationship between the reactivity
of a metal and when it was discovered.
By Sana Amin ,
8B
History of Metals
Metals were known to human since the ancient times.
However they didn’t know how to make use of metals
in the best way. For them it was just a tool to make
arrows and spear tips. Later did they find the more
helpful use of metals such as building material for
various objects. The knowledge of its refining and
processing to yield a useful product took thousands of
years. We will analyze information to see if there is a
relationship exists between the reactivity of a metal and
when it was discovered.
First Metals
The first metals that were used by humans were gold and copper. The softness
and malleability of gold meant it was mainly used for ornamental purposes.
Copper, the more harder metal was used for spearheads, knives, pins and other
useful items
Here is the timeline of the discovery of the first metals.
(1) Gold 6000BC
(2) Copper 4200BC
(3) Silver 4000BC
(4) Lead 3500BC
(5) Tin 1750BC
(6) Iron, smelted, 1500BC
(7) Mercury, (ca) 750BC
Gold
Gold the least reactive of metals was discovered the earliest
in 6000BC . Gold was considered important even then .
Many ancient central American tribes believed in the
importance of gold for religious beliefs . The Inca’s believed
it was the sweat of their sun god that’s why the Incas
honored him with magnificent golden artworks. The
presence of gold eventually led to their destruction as the
Spanish conquistadors (conquerors) plundered them under
their leaders, Pizarro and Cortes. This shows us the social
affects some metals have had on civilizations. Even in recent
times South Africa was colonized by Europeans because of
its vast gold reserves.
Medieval Metals
As the means of technology improved such as the
discovery of fire and use of mining tools, more metals
were discovered. People found different uses for the
softer metals and replaced making of tools and
weapons with the newer harder metals. For example
copper was used to make the blades of swords and
spear tips, after tin was discovered people started using
copper in pottery as tin was more efficient in making
weapons than copper was.
Newer Methods discover newer
metals
There are various methods of extractions. Smelting is when an ore is heated to high
temperatures to separate a metal from its impurities. This method is commonly used to
extract Iron. Another common method is Electrolysis. Which utilizes passing electricity
through a solution to separate metals. Likewise displacement of metals technology can
be used to remove a metal from its compound. For example in class we learnt that we
can separate copper from Copper Sulphate solution by mixing it with magnesium. Listed
below are some metals that were discovered later on.

Zinc – was discovered in Germany by the chemist Andreas Marggraf in 1746. It was
isolated two years later by Anton von Swab. It was isolated by heating calamine and
carbon.

Aluminum - was discovered in Denmark by Hans Christian Oersted in 1825. It is
obtained by performing the electrolysis method.

Sodium – was first isolated by Sir Humphry Davy in 1807 by passing an electric current
through molten sodium hydroxide.

Magnesium- was discovered by Joseph Black, in England, in 1755. It was first isolated by
Sir Humphry Davy, an English chemist, through the electrolysis of a mixture of
magnesium oxide and mercuric oxide in 1808. Today, magnesium is most often
obtained from seawater.
Relative reactivity of metals
Now that we have some information about discovery of
metals let us analyze the reactivity series. The Reactivity Series
is a list of metallic elements, where the more reactive metals
are listed at the top and less reactive ones at the bottom.
Some metals react more easily than others. The reactive
metals react quickly with acid, oxygen, and water. The alkali
metals are a very reactive group of metals.
Size of an atom vs. reactivity
The further down a group an atom is, the larger the
atom is, and the more reactive the element is. The
reactivity of metals increases as you go down the group
because the outer electrons are further from the
nucleus as the atom is larger. This means that it is
harder for the nucleus to keep a pull on the outer
electron making the metal reactive. For example the
highly reactive metal Cesium which is located in group
1 of the periodic table therefore an alkali metal has the
atomic number of 55 which means it has 55 electrons.
Reactivity series of metals
An element is more reactive if it is further to the left of
the periodic table or further down. The exceptions to
this are the transition metals as they have special D
electrons.
Reactivity vs. discovery
Metal
Date of Discovery (
approximately )
Reactivity
( relative position)
Gold
6000BC
2 (Least reactive)
Iron
1200BC
8
Zinc
1746
9
Aluminum
1825
11
Magnesium
1755
12
Potassium
1807
15 (Highly reactive)
3000
2000
1000
0
-1000
-2000
-3000
-4000
-5000
-6000
-7000
Date of Discovery (
approximately )
Reactivity ( relative
position)
Relationship
As you can see with the exception of aluminum there is
a relationship between the reactivity of a metal and the
date it was discovered. The data shows that least
reactive metals were discovered earlier because they
exist in nature in almost pure form. The least reactive
metals such as gold and copper exist naturally and can
be found in form of nuggets. The more reactive metals
exist in compound form and need advanced
technology to separate them. Even today there are
many metals which can only be extracted to its pure
form in a laboratory only.
Conclusion
In conclusion I would like to say that there is a direct
relationship between when a metal was discovered and
it reactivity. Science has played a vital role in discovery
of newer metals which had a very big impact on the
lives we live today. For example without the discovery
of electrolysis scientist may have never discovered
aluminum and with out aluminum we might have
never had the airplanes we have today. Airplanes allow
us to travel long distances much quickly than the old
air travel like that of using blimp.
Bibliography
file:///Users/SanaAmin/Documents/School/Science/Metals%2
0Unit/Reactivity%20series%20%20Wikipedia,%20the%20free%20encyclopedia.webarchive
ile:///Users/SanaAmin/Documents/School/Science/Metals%2
0Unit/Alkali%20Metals.webarchive
file:///Users/SanaAmin/Documents/School/Science/Metals%2
0Unit/History%20of%20Metals.webarchive
http://www.facts-about.org.uk/science-element-magnesium.htm
http://image.wistatutor.com/content/metals-non-metals/metalsreactivity-series.jpeg
http://richardbowles.tripod.com/chemistry/reactivity/reactivity.h
tm
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