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. 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. In other words, periodicity is the idea that elements in a group have similar chemical properties because they have the same valence shell electronic configuration. Over time these gaps have gradually been filled in as scientists unearthed new elements. Periodicity is the repetition of the similar properties of the elements placed in a group separated by certain definite gaps of atomic numbers.
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. Meanwhile, elements in the same period have the same number of occupied electron shells. Elements in the same group have the same number of valence electrons. However, the first scientific discovery of an element occurred in 1649 when Hennig Brand discovered phosphorous. The periodic table is organized into groups (vertical columns), periods (horizontal rows), and families (groups of elements that are similar). 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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