The periodic table was invented by chemist Dmitri Mendeleev to organize and compare elements and understand their relations with each other. Mendeleev created the periodic table between 1868 and 1870 while writing his book titled "The Principles of Chemistry." Initially, Mendeleev created the chart for his personal benefit, but others quickly discovered its value, leading to its immediate acceptance and use by fellow chemists upon publication.
Mendeleev devoted much of his time in the late 1860s and early 1870s to identifying and comparing elements. He frequently discovered new elements while performing experiments, but had no way of keeping track of his findings. Consequently, he began jotting down new elements on paper, but quickly realized that he needed a way to sort and organize them for easy future reference. Mendeleev began loosely organizing a chart, which grouped elements according to their atomic weights. As he plotted elements in horizontal rows on his chart, Mendeleev noticed a distinct pattern begin to appear, but only when he left blanks in the chart. According to the American Institute of Physics, the spaces in between elements in the horizontal rows made elements with like chemical properties appear in regular, predicable patterns in vertical columns on the periodic table.Learn More
A group on the periodic table is one of the vertical columns found on the table. The elements found in the same group all possess the same number of electrons in their outer orbital shell. These electrons are specifically known as valence electrons.Full Answer >
The periodic table was built to show the relationships among the various elements. The periodic table was constructed in 1869 by Dmitri Mendeleev.Full Answer >
The horizontal rows on the periodic table of the elements are called periods. Every element in a period has the same number of atomic orbitals. For instance, hydrogen and helium are in the first period, so they both have electrons in one orbital.Full Answer >
"Rn" stands for radon in the periodic table. Radon's atomic number is 86, and its atomic weight is 222. Radon was originally called niton when it was discovered in 1900.Full Answer >