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Date: 8-3-2017
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Chemistry of Nicke
Nickel had been in use centuries before its actual discovery and isolation. As far back as 3500 BC Syrian bronzes contained a small amount of the element. In 235 BC, coins in China were minted from nickel. However there was no real documentation of the element until thousands of years later. In the 17thcentury, German miners discovered a red Colored ore they believed to contain copper. They discovered upon analysis that there was no copper but that a useless, smelly material was actually present. Thinking the ore was evil they dubbed it "Kupfernickel" or Old Nick's Copper, which meant false or bad copper. Swedish scientist Baron Axel Frederich Cronstedt in 1751 finally isolated nickel from an ore closely resembling kupfernickel. Hence, he named this new element after the traditional mineral.
At the time of its discovery nickel was thought to be useless but as its valuable properties came to light the demand for the metal increased dramatically. The usefulness of nickel as a material in alloys was eventually discovered as the strength, corrosion resistance and hardness it adds to other metals came to be appreciated. In the 1800s, the technique of silver plating was developed with a nickel-copper-zinc alloy being utilized in the process. Today, stainless steel, another nickel containing alloy, is one of the most valuable materials of the 20th century.
The U.S. five-cent piece is 25% nickel. The element is also an important alloying agent for stainless steels and in very powerful magnets. Nickel is found in the earth's crust to the extent of about 70 parts per million, about the same as copper and zinc. There is a good chance that a high proportion of the core of the earth is molten nickel.
Unlike its near neighbor copper on the periodic table, nickel is only a fair electrical conductor. But like its other neighbor, cobalt, it is very useful in making strong permanent magnets. It is also highly resistant to attack by alkalis and is used to store and transport concentrated sodium and potassium hydroxide. Nickel reacts with most acids to produce hydrogen gas and the green Ni2+ ion.
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دراسة يابانية لتقليل مخاطر أمراض المواليد منخفضي الوزن
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اكتشاف أكبر مرجان في العالم قبالة سواحل جزر سليمان
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اتحاد كليات الطب الملكية البريطانية يشيد بالمستوى العلمي لطلبة جامعة العميد وبيئتها التعليمية
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