Relationship Between Metals and Their Discovery By: Ghaida Odah 8C

Introduction In this presentation we are going to investigate the relationship between the reactivity of a metal and the date of it’s discovery. I think that the more reactive the metal is the later on it was found because the least reactive metals like gold and platinum to not tarnish or turn dull and they are found on the earth’s crust uncombined with other elements so people would find shiny pieces of the on the ground or in streams even if they were rare like gold.

Reactivity Series

Potassium Discovery Potassium is a very reactive alkaline metal that was discovered and isolated from potash in 1807 by English Chemist Sir Humphrey Davy. Due to the difficulty of extracting potassium found in minerals the English chemist developed a new method for extracting potassium. Extraction In order to extract potassium English chemist Davy used a new method of isolating elements that he had invented, electrolysis. In electrolysis, an electric current is passed through a melted compound causing the compound to break into its elements Properties Soft Dense Very Reactive Low Melting point of 63°C Boiling Point of 770°C Good conductor of heat Good conductor of electricity Uses Fertilizers Fireworks Neutralization of acids Used as a medium for heat transfer Used in inks, dyes, safety matches, fly paper etc. Used in gold mining

Sodium Discovery Sodium is a very reactive alkali metal but its still less reactive than potassium. It was also discovered in 1807 by Sir Humphrey Davy. The reason it wasn’t discovered until then is because it attaches itself to other elements so it’s hard to break apart so Sir Humphrey needed to use a new method. Extraction Extracting the pure sodium metal needs electrolysis just like potassium. Since there isn’t much demand for the sodium metal but rather for sodium compound different methods are used like the chloralkali process which is one of the most important industrial processes used today. Properties Soft Shiny Very Reactive (water, oxygen, snow) Melting point of 97.82°C Boiling Point of 881.4°C Low density Good conductor of electricity Uses Ordinary table salt Baking Soda Baking Powder Household products (soap/detergents) Aspirin and other drugs Heat exchange medium in nuclear power plants.

Calcium Discovery Calcium is a reactive alkaline earth metal commonly found in the earth’s crust. Calcium was used for hundreds of years but wasn’t prepared in pure form until 1808 by Sir Humphrey Davy. The same method that was used for the extraction of potassium and sodium was used for calcium Extraction Just like sodium the calcium metal wasn’t really in demand but it’s compounds were. The calcium metal is obtained using electrolysis but most calcium compounds are found all around the world such as limestone which is one of the most important chemicals in the world. Properties Hard Dense Very Reactive Melting point of 850°C Boiling Point of 1440°C Light weight Good conductor of electricity Uses Fertilizers Fireworks Neutralization of acids Used as a medium for heat transfer Used in inks, dyes, safety matches, fly paper etc. Used in gold mining

Magnesium Discovery Magnesium is a an alkaline earth metal in Group 2 of the periodic table. In 1755 magnesia was found which was a compound. Centuries before that humans used magnesium compounds. It wasn’t until 1808 when Sir Humphrey Davy isolated the element. Extraction There are two methods for extracting magnesium. The first method is by using electrolysis just like some of the other metals mentioned earlier. The second method involves reacting magnesium oxide with ferrosilicon which is an alloy of iron silicon. Properties Hard Light ( lightest of all structural metals) Fabricated Melting point of 651°C Boiling Point of 1100°C Fairly Reactive Good conductor of heat and electricity Uses Alloys for airplanes and automobiles Fireworks Metal luggage Cameras Power Tools Gardening equipment Ladders

Aluminum Discovery Aluminum is a metal found in the periodic table in Group 13. Aluminum occurs naturally in compounds never as a pure metal so it is quite difficult to extract so pure aluminum so the element on it’s own wasn’t discovered until about 1825 by Hans Christian Oersted. Extraction About a hundred years ago extracting aluminum was very hard and expensive but nowadays aluminum can be extracted using 2 steps. The first step is separating aluminum oxide from bauxite using the Bayer then by treating the aluminum oxide using a process similar to the Hall method. Properties Dense Malleable Ductile Melting point of 660°C Boiling Point of 2327-2450°C Good conductor of electricity Light Weighted Uses Aircrafts and airplanes Chemical equipment Aluminum alloys used in everyday kitchen utensils Car and truck manufacturers Soft drink cans Paint tubes

Zinc Discovery Zinc, according to records was discovered by German scientist Andrea Margraf in 1746, though many historians agree that it was used by ancient people long ago. Some scientists say that it was alloys of zinc that people were familiar with not the element on its own. Nobody is absolutely sure. Extraction There are two ways to extracting zinc. The first method is by heating the zinc in air which converts the zinc ore into a compound of zinc and oxygen that can then be separated by heating it with charcoal. The second methods using electrolysis which is used for a lot of metals. Properties Fairly soft Dense Fairly Reactive Melting point of 419.5°C Boiling Point of 908°C Malleable at 100 to 150°C Reasonable conductor of electricity Uses Galvanizing Alloys such as brass Paint Rubber Products Floor Coverings Electrical Equipment Ointments

Copper Discovery Copper was one of the earliest elements known to man. It is a transition metal. Nobody knows who exactly discovered Copper but some sources say that it was discovered around 4200 B.C. but nobody is absolutely sure so basically the date is known to the ancients only. Extraction The method that is used to remove copper from its ores depends on the kind of ore used. Some methods take very long time and don’t always leave us with copper that is pure enough so electrolysis is used commonly and by repeating it the copper will become 99.9 percent pure. Properties Soft Moderately reactive Ductile Melting point of 1083°C Boiling Point of 2595°C Excellent conductor of electricity Good conductor of heat Uses Electrical wiring Roofs (from alloys of copper) Heating and Plumbing systems (from alloys of copper) Bells (from alloys of copper) Saute and frying pans Gun metal (from alloys of copper)

Silver Discovery Silver has been classified as a precious metal. It is a transition metal. It has been used by humans for thousands of years. The date of discovery and the discoverer are not accurate but some sources say thet silver was discovered in 4000 B.C. but nobody is absolutely sure. Extraction Silver often occurs as a free element in nature and extracting it from its ores is fairly easy. Ores rich in silver have disappeared so it usually comes in small amounts from the ores of other metals so most of the time it’s left in the waste of a metal and is extracted using electrolysis. Properties Dense Malleable Ductile Melting point of 660°C Boiling Point of 2327-2450°C Excellent conductor of electricity Light Weighted Uses Coins Jewelry Artwork Electrical and electronical equipment Silverware Photography Water purification

Gold Discovery Gold has been called the most beautiful of all chemical elements. It was one of the first pure metals to be used by humans. The date of discovery and discoverer are not accurate but gold objects dating 2600 B.C. have been found and some sources say that it was found on 6000 B.C. Extraction There are at least two main ways to remove gold from its ores. One is to mix an ore with mercury metal. It combines with the gold and forms and amalgam, which is a mixture of two or more metals on of which is mercury. Then the gold amalgam is removed and heated giving us pure gold. Properties Soft Malleable Ductile Melting point of 1064.76°C Boiling Point of 2700°C Dense Not very reactive Uses Medals Jewelry Artwork Industries Medical (treating cancer/dentistry) Electronics (mobile phones and computers)

Metal Discovery Timeline Date of Discovery Potassium 1807 Sodium Calcium 1808 Magnesium 1755 Aluminum 1825 Zinc 1746 Copper 4200 B.C. Silver 4000 B.C. Gold 6000 B.C.

If you noticed in the picture earlier how potassium, sodium, calcium and magnesium all reacted with the water. Potassium reacted violently so did sodium and calcium had some sort of visible reaction while the rest of the metals just sunk in the water. If you notice how the metals that reacted the most were the ones that were discovered latest which proves that the more reactive the metal the later on it’s discovered. Also the same thing happened with the reaction with hydrochloric acid, the metals that were most reactive were discovered latest.

Conclusion Now before I started investigating the relationship I thought that the more reactive the metal the later on it was discovered and that was true for most of the metals except for two of them. Now Aluminum is less reactive than magnesium yet it was discovered later on. After reading more about the extraction of aluminum I realized that aluminum was discovered before magnesium but not as an element, as a compound and it took a lot of time to come up with a way to isolate it and it cost a lot while isolating magnesium was easier and cheaper.

Another thing that caught my attention was how copper is more reactive than silver but it was discovered before silver. Again after reading more about the extraction of both metals I found out that 1Silver was probably first discovered after gold and copper. Gold and copper often occur as free elements in nature. This sentence explained why silver was discovered before copper. So basically my hypothesis was correct but there were some exceptions that were explained.

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