Attempts to classify materials such as these resulted in the concepts of classical elements, alchemy, and various similar theories throughout human history. The history of the discovery and use of the elements began with primitive human societies that discovered native minerals like carbon, sulfur, copper and gold (though the concept of a chemical element was not yet understood). Air is primarily a mixture of molecular nitrogen and oxygen, though it does contain compounds including carbon dioxide and water, as well as atomic argon, a noble gas which is chemically inert and therefore does not undergo chemical reactions. Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. Only a few elements, such as silver and gold, are found uncombined as relatively pure native element minerals. When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds. Atoms can be transformed into different elements in nuclear reactions, which changes the atom's atomic number.Īlmost all of the baryonic matter of the universe is composed of chemical elements (among rare exceptions are neutron stars). Two or more atoms of the same element can combine to form molecules, in contrast to chemical compounds or mixtures, which contain atoms of different elements. For example, oxygen has an atomic number of 8, meaning that each oxygen atom has 8 protons in its nucleus. Chemical elements are identified by the number of protons in the nuclei of their atoms, known as the element's atomic number. The basic particle that constitutes a chemical element is the atom. Not to miss out, element 102, Nobelium, No, is named in honor of Alfred Nobel, who set aside his vast fortune to establish Nobel Prizes.A chemical element is a chemical substance that cannot be broken down into other substances by chemical reactions. Mendeleev never received a Nobel Prize for his work, but element 101 was named Mendelevium, Md, after him. For instance they discovered phosphorus when they isolated it from urine. Over time these gaps have gradually been filled in as scientists unearthed new elements. Not only did Mendeleev arrange the elements in the correct way, but he also had the foresight to leave gaps for undiscovered elements. At that time, he had only 50 elements to arrange. He wrote the properties of the elements on pieces of card and rearranged them until he realised that, by putting them in order of increasing atomic weight, certain properties of elements regularly occurred. Then in 1869, a Russian scientist called Dmitri Mendeleev produced one of the first practical periodic tables. Several other attempts were made to group elements together over the coming decades. The earliest attempt to classify the elements was in 1789, when Antoine Lavoisier grouped the elements based on their properties into gases, non-metals, metals and earths. The discovery of other elements followed regularly and soon it became necessary to arrange them in some sort of order. However, the first scientific discovery of an element occurred in 1649 when Hennig Brand discovered phosphorous. Copper has been used by humans for as much as 7000 years and elements such as gold, silver, tin, lead and mercury have been known for many thousands of years.
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