The Periodic Table of Elements can be used as an assisting tool in chemical calculations, when a specification of an element is needed it is easily found in the Periodic Table. The periodic table also gives us an idea of what the characteristics of an element might be and help us predict how an element might react based on in which group it is located.
The Periodic Table has constantly been improved and developed over the past 200 years, but in 1869 Dimitri Mendeleev finished the first version of the periodic table as we know it today, by arranging the elements by atomic mass and leaving spaces open for the elements that were not yet discovered. We created a timeline of the history of the periodic table..
The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass.
Although Mendeleev's table demonstrated the periodic nature of the elements, it remained for the discoveries of scientists of the 20th Century to explain why the properties of the elements recur periodically. For example, in 1911, A. van den Broek in a series of two papers proposed that the atomic weight of an element was approximately equal to the charge on an atom. This charge, later termed the atomic number, could be used to number the elements within the periodic table. With the discovery of isotopes of the elements, it became apparent that atomic weight was not the significant player in the periodic law as Mendeleev, Meyers and others had proposed, but rather, the properties of the elements varied periodically with atomic number. The last major changes to the periodic table resulted from Glenn Seaborg's work in the middle of the 20th Century. Starting with his discovery of plutonium in 1940, he discovered all the transuranic elements from 94 to 102. He reconfigured the periodic table by placing the actinide series below the lanthanide series. In 1951, Seaborg was awarded the Nobel Prize in chemistry for his work. Element 106 has been named seaborgium (Sg) in his honor.
The Periodic table is useful for modern students and scientists because it helps predict the types of chemical reactions that a particular element is likely to participate in. Rather than memorize facts and figures for each element, students and scientists need only glance at the table to learn much about the reactivity of an element, whether it is likely to conduct electricity, whether it is hard or soft, and many other characteristics. Another useful feature of the periodic table is that most tables provide all the information you need to balance chemical reactions at a glance. The table tells each element's atomic number and usually its atomic weight. The usual charge on an element is indicated by an element's group.
The periodic table is a chart that organizes the arrangement of the known and recognized chemical elements. The organization on the table is based on the atomic weight, electron configurations, and chemical properties of the elements. The elements are shown according to their increasing atomic weights, starting with the smallest and gradually moving up to the highest weights.
Most people have been seeing the periodic table on classroom walls since grade school, and most people probably think it never changes. They're wrong. The periodic table is much more fluid than the majority of people realize. It's still changing today.
The first periodic table in the \"rows and columns\" form we see today was invented by Dmitri Mendeleev in 1869. It included the properties of all of the known elements of that time. Mendeleev predicted that the discovery of some as-yet unknown elements would fill in some of the gaps on his table at some point in the future, and he was correct.
The periodic table has long-since filled in Mendeleev's gaps and has added new elements. It has even changed the weights of other elements. The periodic table is continually being changed as new discoveries are made and new theories are developed to explain the behavior of chemicals.
A huge number of changes were made to the periodic table in the early parts of the 20th century. However, some interesting and significant changes have been made as recently as the past 20 years. For example, two brand new elements were discovered in 2004 and 2006 respectively, and added to the periodic table in 2012. These elements are flerovium (element 114) and livermorium (element 116).
Flerovium and livermorium are short-lived elements, each lasting only seconds or less. They are lab-created elements that scientists made as side effects of smashing the atoms of other elements together to see what they would do. These aren't elements you'll likely find out in nature, but they are elements nonetheless and now have proud places on the periodic table.
These two new elements now make the number of elements displayed on the periodic table 117. However, only 114 of these elements are officially recognized by the scientific community. Elements 113, 115, and 117 have not yet been officially accepted as genuine elements.
The number of elements on the periodic table isn't the only thing about the table to change in the past 20 years. The atomic weights of some elements on the table have also been changed. These changes were made by the International Union of Pure and Applied Chemistry (IUPAC), which is the organization that oversees the official periodic table.
This made their weights better expressed as intervals of numbers rather than as single numbers. Bromine used to have an atomic weight of 79.904 on the periodic table. It now has an interval of 79.901 to 79.907. As for magnesium, it once had an atomic weight of 24.3050. Now, the periodic table shows it as 24.304 to 24.307. The elements germanium, indium, and mercury are also expected to get official atomic weight changes on the periodic table in the near future.
As new discoveries continue to be made, the periodic table will continue to change. It is almost like a living document in that it grows and expands as new information is fed to it. The periodic table of 20 years ago is gone. The periodic table of 20 years from now is still waiting to be discovered. 1e1e36bf2d