Element periodic properties

For the purposes of fixing the stationary states we have up to this point only considered simply or multiply periodic systems. However the general solution of the equations frequently yield motions of a more complicated character. In such a case the considerations previously discussed are not consistent with the existence and stability of stationary states whose energy is fixed with the same exactness as in multiply periodic systems. But now in order to give an account of the properties of the elements, we are forced to assume that the atoms, in the absence of external forces at any rate always possess sharp stationary states, although the general solution of the equations of motion for the atoms with several electrons exhibits no simple periodic properties of the type mentioned (Bohr [1923]). 

A detailed discussion of redox reactions must wait until Chapter 19, after we explore the nature of the atom, periodic properties of the elements, and thermodynamics. For now, we focus on only a few types of redox reactions that are common and relatively simple. 

Ion formation is only one pattern of chemical behavior. Many other chemical trends can be traced ultimately to valence electron configurations, but we need the description of chemical bonding that appears in Chapters 9 and 10 to explain such periodic properties. Nevertheless, we can relate important patterns in chemical behavior to the ability of some elements to form ions. One example is the subdivision of the periodic table into metals, nonmetals, and metalloids, first introduced in Chapter 1. 

The periodic table orders the elements in a way that helps chemists understand why atoms behave as they do. What makes fluorine react violently with cesium while its nearest neighbor neon is reluctant to react with anything In other words, what gives the elements their properties and what order lies below the surface of their seemingly random nature Scientists know now that the periodicity of the elements is due largely to recurring patterns in their electron configurations. 

Identify various elements a computer with by using your understand- access to the ing of periodic properties Internet... 

The representation of the periodic system in this book shows yet another perspective. Each element has not only its own history but also its own identity. This is determined by the number of protons in the nucleus (the atomic number) and the corresponding number of electrons in the atomic shell. These electrons, in turn, give each element their properties, their "personalities", so to speak. There are relationships, but each element is unique in the sum of its properties. The text describes the particularities of each element, and the chosen picture indicates a scene from everyday life where we would encounter... 

There are three distinct areas of the periodic table—the main group elements, the transition group elements, and the inner transition group elements. We will focus our attention at first on the main group elements, whose properties are easiest to learn and to understand. 

A plot of density versus element is given below (table only shows a few elements used in the plot. Density clearly is a periodic property for these two periods of main group elements. It rises, falls a bit, rises again, and falls back to the axis, in both cases. 

Periods are the horizontal rows on the periodic table the elements have properties unlike the other members of the period. 

Palladium is the middle element in group 10 of the transition elements (periods 4, 5, and 6). Many of its properties are similar to nickel located above it and platinum just below it in this group. 

Chemical patterns based on periodic properties of elements... 

But when chemist Philip Abelson joined McMillan in 1940, he quickly proved that eka-rhenium was indeed a new element, with properties similar to uranium. McMillan named it neptunium , after Neptune, the next planet out from Uranus. It was the start of a voyage into the outer reaches of the Periodic Table. ... 

Periods The rows are called periods. As you move across any period, you pass over a series of elements whose properties change in a predictable way. 

The whole point of the periodic table, aside from providing interior decoration for chemistry classrooms, is to help predict and explain the properties of the elements. These properties change as a function of the numbers of protons and electrons in the element. 

These are prepared by fusion from the elements. Their properties vary across the periodic tabic, those of the alkalies and alkaline earths being readily hydrolyzed by H20 or acids and are stoichiometric, while the arsenides of the other metals show an increasingly mtermelallic character and resist hydrolysis. 

One of the many periodic properties of the elements that can be explained by electron configurations is size, or atomic radius. You might wonder, though, how we can talk about a definite "size" for an atom, having said in Section 5.8 that the electron clouds around atoms have no specific boundaries. What s usually done is to define an atom s radius as being half the distance between the nuclei of two identical atoms when they are bonded together. In the Cl2 molecule, for example, the distance between the two chlorine nuclei is 198 pm in diamond (elemental carbon), the distance between two carbon nuclei is 154 pm. Thus, we say that the atomic radius of chlorine is half the Cl-Cl distance, or 99 pm, and the atomic radius of carbon is half the C-C distance, or 77 pm. 

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