Periodic table left-step form

The problem is no longer the validity of Mendeleev s system, but the best way to represent it. Should it be the original short-form table with 8 columns, the familiar medium-long form with 18 columns, or perhaps even a long-form table with 32 columns, which more naturally accommodates the rare earth elements Into the main body of the table Altanahvely, some favor pyramidal tables, while others advocate the left-step form proposed by diaries Janet in the 1920s. Theodor Benfey and rhilip Stewart have proposed continuous spiral models. Hundreds, possibly even thousands, of periodic systems have been proposed, and each has its ardent supporters. 

Both Z and N decrease by two units, and the mass number A (number of protons plus number of neutrons, A=Z+N) is four units lower than the mass number of the mother nuclide. Thus a new element located two steps to the left in the periodic table has been formed. 

What actually converted me to the left-step table, at least for a period of a few years, was a rather concise paper by the periodic table designer Gary Katz, which appeared in The Chemical Educator.20 My own support for this form of the table centered on my interest in the dual sense of the term element and in particular the more fundamental sense, called element as a basic substance by Paneth. 

ABSTRACT This article concerns various foundational aspects of the periodic system of the elements. These issues include the dual nature of the concept of an "element" to include element as a "basic substance" and as a "simple substance." We will discuss the question of whether there is an optimal form of the periodic table, including whether the left-step table fulfils this role. We will also discuss the derivation or explanation of the [n + , n] or Madelung rule for electron-shell filling and whether indeed it is important to attempt to derive this rule from first principles. In particular, we examine the views of two chemists, Henry Bent and Eugen Schwarz, who have independently addressed many of these issues. 2008 Wiley Periodicals, Inc. Int J Quantum Chem 109 959-971, 2009... 

It should also be said that the reason why Bent and Weinhold devote such attention to the n + ( rule is that, as mentioned earlier, the rule is clearly represented on the left-step table, the form of the periodic table that they favor. In addition, as was mentioned, the authors believe that the best representation of the periodic system should be based on the electronic structure of the neutral atoms of all the elements and not on their macroscopic properties. 

The portion of the periodic table that contains the metallic elements is shown here in gray, and the portion that contains the nonmetallic elements is shown in light blue. The stair-step line that starts between B and Al on the periodic table and descends between Al and Si, Si and Ge, and so on separates the metallic elements from the nonmetallic elements. The metals are below and to the left of this line, and the nonmetals are above and to the right of it. Most of the elements that have two sides of their box forming part of the stair-step line are metalloids. Aluminum is usually considered a metal. 

Copper is a typical metal. It is lustrous (although it tarnishes readily) it is an excellent conductor of electricity (it is widely used in electrical wires) and it is readily formed into various shapes, such as pipes for water systems. Copper is one of the transition metals—the metals shown in the center of the periodic table. Iron, aluminum, and gold are other familiar elements that have metallic properties. All of the elements shown below and to the left of the heavy "stair-step" black line in Figure 3.7 are classified as metals, except for hydrogen (see Figure 3.9). 

The Periodic Table is divided into two sections by a stair-stepped line (Figure 2.4). The line starts under hydrogen, goes over to boron, and then stair-steps down one element at a time to astatine or radon, depending on which Periodic Table is used. The 81 elements to the left and below the stair-stepped line are metals. Metals make up about 75% of all the elements. Metals lose their outer-shell electrons easily to nonmetals when forming compounds. Metals are malleable (they can be flattened), ductile (they can be drawn into a wire), and conduct heat and electricity quite well. The farther to the left of the line you go, the more metallic the properties of the element the closer to the line, the less metallic the properties of the element. Metallic properties increase as you go down a column on the Periodic Table. All metals are solids, except gallium, mercury, francium, and cesium, which are liquids under normal conditions. 

The idea of attributing Z alone (at least for some level of chemical comprehension) was shown by Scerri to be fruitful in deciding upon the best form of the Periodic Table. In this respect, although he previously proposed the option for the left-step long form, as based on Madelung rule, he recently has revived the atomic triads idea, i.e., among thee elements placed one in top of other in neighborhood... 

In addition to the short and long forms of the modern periodic table, another increasingly popular display is called the left step or Janet periodic table. Do an Internet search to find a representation of this form. Why is it called a Janet table Provide a reference in your answer. 

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