Does a
Relationship Exist
between the
Reactivity of a
Metal & When it
was Discovered?
Isha Lamba
8B Science
To answer this question let’s
examine some facts and historical
information.
Majority of the known elements are metals.
 Majority of the known elements are
metals.
 Today mankind knows of 86 metals out
of a total of 112 elements.
 The first two metals to be discovered
were gold and copper.
We have learnt that different important metals can be
arranged in the order of their decreasing reactivity as:
K
Na
Ca
Mg
Al
Zn
Fe
Pb
Cu
Ag
Hg
Au
And here is the timeline
representing the discovery of
different metals included in this
reactivity series…
However, a more comprehensive list can be recognized as:-
And here is the information about the dates of
discovery for each of these metals
Discovered Metal
K
Na
Li
Sr
Ca
Mg
Al
Zn
Cr
Fe
Cd
Co
Ni
Sn
Pb
Cu
Ag
Hg
Au
Pt
Year
1807
1807
1817
1790
1808
1808
1825
1746
1797
-1500
1817
1737
1751
-1750
-3500
-4200
-4000
-750
-6000
1735
The First Metal to be Discovered - Gold
 Gold has been used since 6000 BC
 Gold is virtually placed at the bottom of
the Reactivity series.
Gold came into use the
first because of some
special properties…
Gold – Facts:
 Shining Yellow Color: The symbol for gold is Au, which
represents abbreviated form of the Latin word – ‘Aurum’,
meaning ‘shining dawn’.
 In case of the earliest metals, their color was a very important
property as this is what allowed the metals to be recognized
in the surrounding rock, stones, gravel and dirt (and evoked
interest) as well as enabled their separation from them in the
earliest days.
 Gold is found uncombined in nature >> this fact also helped its
discovery and subsequent use.
 Gold is virtually noncorrosive and tarnish free (as it does not
get oxidized) >> this made it attractive to man.
All these facts and properties of
Gold are related to (and can be
explained based on) the lack of
reactivity of Gold.
The Next Metal to be Used by
Man: Copper
 Copper was discovered in 4200 BC
 The first metallic tools, implements and weapons
were made from copper.
 Copper also is found free besides also being found
in the form of minerals like cuprite, malachite,
azurite, chalcopyrite and bornite.
In the Reactivity-Series (in the order
of reactivity) Copper again comes in
the bottom block (amongst the
elements with low reactivity)
Until the end of the 17th century (and for a large span
of some 7700 years), only 12 metals were known.
 Gold
 Tin
 Silver
 Platinum
 Copper
 Antimony
 Lead
 Bismuth
 Mercury
 Zinc
 Iron
 Arsenic
Seven out of these twelve metals were the metals
upon which the ancient civilizations were based.
They were:
 Gold (discovered in 6000BC)
 Copper (discovered in 4200BC)
 Silver (discovered in 4000BC
 Lead (discovered in 3500BC)
 Tin (discovered in 1750BC)
 Iron (discovered in 1500BC)
 Mercury (discovered in 750BC)
So, these metals are known as Metals of Antiquity.
All of them find a place in the lower part
of the reactivity series (with the
exception of Iron that is towards the
middle of the series).
 The other four of these twelve metals - arsenic,
antimony, zinc and bismuth, were discovered in the
thirteenth and fourteenth centuries.
 Arsenic, antimony and bismuth are not shown in the
reactivity series but Zinc is included in the reactivity
series and occupies a place just a little higher than Iron
(appropriately).
 Platinum which was discovered in the 16th century –
so far forms the only big exception from the trend (the
lower the reactivity of the metal, the earlier was it
discovered).
The next 12 metals were
discovered in the 18th Century
 Cobalt (1735)
 Uranium (1789)
 Nickel (1751)
 Zirconium (1789)
 Manganese (1774)
 Titanium (1791)
 Molybdenum (1781)
 Yttrium (1794)
 Tellurium (1782)
 Beryllium (1797)
 Tungsten (1783)
 Chromium (1797)
These metals again appear at appropriate place in the reactivity series,
with respect to the trend – the lower the reactivity of the metal, the
earlier it was discovered.
The 41 metals that were discovered in 19th
Century include:
Niobium (1801), Tantalum (1802), Iridium (1803),
Palladium(1803), Rhodium (1803), Potassium (1807), Sodium
(1807), Boron (1808), Barium (1808), Calcium (1808),
Magnesium (1808), Strontium (1808), Cerium (1814), Lithium
(1817), Cadmium (1817), Selenium (1817), Silicon (1823),
Aluminum (1827), Thorium (1828), Vanadium (1830),
Lanthanum (1839), Erbium (1843), Terbium (1843), Ruthenium
(1844), Cesium (1860), Rubidium (1860), Thallium (1861),
Indium (1863), Gallium (1875), Holmium, Thulium, Scandium,
Samarium, Gadalinium, Praseodynium, Neodynium and
Dysprosium (1878-1885), Germanium (1886), Polonium
(1898), Radium (1898) Actinium (1899)
 These 41 metals include metals like Potassium,
Sodium, Calcium, Magnesium and Aluminum
which show on the top of the reactivity series.
 Some of the elements discovered in the later part of
this century are members of Lanthanide and
Actinide series – both of which are known to be very
reactive (and electropositive).
Metals Discovered in the 20th
Century
Europium (1901), Lutetium (1907), Protactinium (1917),
Hafnium (1923), Rhenium (1924), Technetium (1937),
Francium (1939), Promethium (1945), Transuranium
elements - Neptunium, Plutonium, Curium, Americum,
Berkelium, Californium, Einsteinium, Fermium,
Mendelevium, Nobelium, Lawrencium (1940-61)
More members of Lanthanide and Actinide series get discovered –
both of which are known to be very reactive (and electropositive).
Relationship of the discovery time with the
position in the reactivity series
Discovery of Elements as arranged in the order of
their increasing Reactivity
2000
1000
0
-1000
-2000
-3000
Pt
Au
Hg
-4000
Ag
Cu
Pb
Sn
Ni
-5000
Co
Cd
Fe
Cr
Zn
Al
Mg
Ca
-6000
Discovered Element
Sr
Li
Na
K
So the observations suggest a strong
trend – that the lesser the reactivity of a
metal, the earlier was its discovery and
conversely the more the reactivity of a
metal, the later was its discovery.
Conclusion
From the scientific logic, a metal that was reactive was
expected to be occurring in a combined state (in form of its
compounds with other elements), posing a challenge for its
extraction from the ores and needing extra effort both in form
of man’s ability and his knowledge. And as the reactivity of
the metal increased, the level of this challenge also increased.
Naturally with man’s ability having evolved over the years, he
was able to discover the more and more difficult (from
extraction point of view) metals (that were actually more and
more reactive metals) as well as find their virtues and
applications.
Conclusion
The trend does not have to be followed strictly by each
and every metal in relation to each and every metal adjacent
to it, since there may have been certain other determining
factors also (including the chance factor), besides the effect of
this strong scientific factor. But generally if we consider the
metals arranged in the reactivity-series in form of chunks,
then this trend was more or less observed everywhere with
the exception of Platinum (which got discovered too late),
Mercury (which got discovered a bit late) and Iron (which got
discovered a bit too early for the trend).
BIBLIOGRAPHY

Petrucci, Ralph H.. General chemistry: principles and modern applications. 10th ed.
Toronto: Pearson Prentice Hall, 2010. Print.

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2010. <http://neon.mems.cmu.edu/cramb/Processing/history.html>.

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
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
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
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