Families periodic table

Iodine [7553-56-2] I, atomic number 53, atomic weight 126.9044, is a nonmetaUic element belonging to the halogen family in Group 17 (VIIA) of the Periodic Table. The only stable isotope has a mass number of 127. There are 22 other iodine isotopes having masses between 117 and 139 14 of these isotopes yield significant radiation. 

The person whose name is most closely associated with the periodic table is Dmitri Mendeleev (1836-1907), a Russian chemist. In writing a textbook of general chemistry, Mendeleev devoted separate chapters to families of elements with similar properties, including the alkali metals, the alkaline earth metals, and the halogens. Reflecting on the properties of these and other elements, he proposed in 1869 a primitive version of today s periodic table. Mendeleev shrewdly left empty spaces in his table for new elements yet to be discovered. Indeed, he predicted detailed properties for three such elements (scandium, gallium, and germanium). By 1886 all of these elements had been discovered and found to have properties very similar to those he had predicted. 

In Chapter 6 the element hydrogen was characterized as a family by itself. Often its chemistry distinguishes it from the rest of the periodic table. We find this is the case when we attempt to predict the ionic character of bonds to hydrogen. 

The halogens are a family of elements appearing on the right side of the periodic table, in the column just before the inert gases. The elements in this group—fluorine, chlorine, bromine, iodine, and astatine—show some remarkable similarities and some interesting trends in chemical behavior. The similarities are expected since the... 

There are similar, but smaller, trends in the properties of elements in a column (a family) of the periodic table. Though the elements in a family display similar chemistry, there are important and interesting differences as well. Many of these differences are explainable in terms of atomic size. 

Of course it is important to distinguish between the shape of the periodic table, which is admittedly a matter of choice or convention, from tables that actually place certain elements in different groups. The point is not whether one should favor a tabular form, in which periods end abruptly, over circular displays which emphasize the continuity of the sequence of the elements for example. The question is rather whether to favor a table that places the element helium among the noble gases, when compared with tables that place this element among the alkaline earths. The wider question is whether elemental classification is an objective matter of fact or whether it is a matter of convention. It is the question of whether helium, for example, has a natural kinship with the noble gases or with the alkaline earths. Or as philosophers of science are apt to say, it is the question of whether or not groups, or families of elements, represent natural kinds. 

The periodic table is an arrangement of the elements that reflects their family relationships members of the same group typically show a smooth trend in properties. 

NOx An oxide, or mixture of oxides, of nitrogen, typically in atmospheric chemistry, noble gas A member of Group 18/VIlI of the periodic table (the helium family). 

Silicon (Si) is a nonmetallic chemical element of the carbon family (Group rva of the periodic table) and makes up 27.7 percent of the Earth s crust. It is the second most abundant element in the crust, being surpassed only by oxygen. 

A family of colorless, inactive gases was unknown at the time Mendeleev conceived his periodic table. Eventually, these gases were discovered on Earth in the late 1890s. What group does this family occupy in the modem periodic table ... 

The periodic table, which for now is presented only enough to introduce the concepts of periodic groups or families and the numbers of electrons in the outermost electron shells. 

The periodic table is an extremely useful tabulation of the elements. It is constructed in a manner such that each vertical column contains elements which are chemically similar. The elements in the columns are called groups or families. (Elements in some of the groups arc very similar to each other. Elements in others of the groups are less similar. For example, the elements of the first group resemble each other more than the elements of the fourth group from the end, headed by N.) Each row in the table is called a period (Fig. 3-1). 

B Main group elements are in the A families, while transition elements are in the B families. Metals, nonmetals, metalloids, and noble gases are color coded in the periodic table inside the front cover. 

If the seventh period of the periodic table is 32 members long, it will be the same length as the sixth period. Elements in the same family will have atomic numbers 32 units higher. The noble gas following radon will have atomic number = 86 + 32 = 118. The alkali metal following francium will have atomic number = 87+32 = 119. 

A Atomic size decreases left to right through a period, and bottom to top in a family. We expect the smallest elements to be in the upper right comer of the periodic table. S is the element closest to the upper right comer and should have the smallest atom. 

A given main group metal typically displays one oxidation state, usually equal to its family number in the periodic table. Exceptions are elements such as T1 (+1 and+3), Pb (+2 and +4), and Sn (+2 and +4) in which the lower oxidation state represents a pair of s electrons not being ionized (a so-called inert pair ). 

Hypervalency can be defined most simply with respect to purely empirical aspects of chemical periodicity. As beginning chemistry students are taught, each chemical family is associated with a column of the periodic table and associated valence atomic number ZAval, such that the empirical valency FAemp is the minimum shift of ZAval to reach the nearest rare gas,... 

Groups or families are the vertical rows on the periodic table. They may be labeled in two ways. The older way involves a Roman numeral and a letter, either A or B. We call the groups labeled with an A the main-group elements, while the B groups are the transition elements. Two horizontal groups, the inner transition elements, belonging to periods 6 and 7 are normally pulled out of the main body of the periodic table and are placed at the bottom of the table. 

In this chapter, you learned about the atom and the three basic subatomic particles protons, neutrons, and electrons. You also learned about the periodic table and about the classification of the various elements on the periodic table. Classifications include metal, metalloid, nonmetal, and classification according to the family (group) and period. You also learned the difference between ions and molecules, and how to name ionic compounds and molecules systematically. 

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