Periodic table outermost electron configurations

Relate the electron configuration of elements to the arrangement of the elements in the periodic table. Examine the outermost electrons for members of each group A family and see if a pattern develops in the outermost electron configuration for members of the same family. 

The elements display a periodicity of electronic conf uration. For example, if we examine the detailed electronic configurations of the alkali metals, we find that the outermost shell (specifically, the s subshell) of electrons contains only a single electron in each case. The alkahne earth metals have two outermost electrons. The elements within each other group of the periodic table also have similarities in their outermost electronic configurations. We deduce that the outermost part of the electronic configuration is the main factor that determines the chemical properties of the elements because the periodic table was constructed from data about the properties of the elements. 

The properties of the elements stem from their electronic configurations, and the properties place them in their locations in the periodic table. In each group, the elements have a characteristic outermost electronic configuration. The existence of the transition and inner transition elements stems from adding electrons to inner shells after outer shells have been started. Because the periodic table reflects the electronic structures of the atoms, it can be used as a memory device when writing electronic configurations. The ability to write and understand such configurations is a very important skill. (Section 4.8)... 

The periodic table is also organized to correspond to electron configurations within the atom. The table may be divided into blocks corresponding to the subshell of the orbital filled most recently by an electron using the building-up rule (See Skill 1.1b). Elements in the same column have similar properties because they have the same valence (outermost) electron configurations. These are the electrons that are most important in determining chemical properties. 

Although each of the elements described in Problems 2.24 and 2.25 has a unique electron configuration, each has the same outermost electron configuration. Since they are in the same group of the Periodic Table, and therefore have similar chemical properties, quantum mechanics has explained, most importantly, that the chemical properties of the elements depend not on the total number of electrons (or atomic number) but principally upon the configuration of the electrons in the outermost shell. This means the group number is in fact the number of electrons in the outer shell of the representative elements, and the principal quantum number is identified with the period. 

At the bottom of the graph in Figure 2.22 are the Group lA elements (the alkali metals), which have the lowest first ionization energies. Each of these metals has one valence electron (the outermost electron configuration is ns ), which is effectively shielded by the completely filled inner shells. Consequently, it is energetically easy to remove an electron from the atoms of the alkali metals to form unipositive ions (Li, Na, K, . . . ) that are isoelectronic with the noble gases that precede them in the periodic table. 

Hence the general electron configuration of the valence shell for the group 13 elements is ns nph The electrons in the outermost energy level are the valence electrons and involved in bonding. The position of an element in the periodic table can be deduced from its outermost electron configuration. 

Copper is the first member of Group IB of the periodic table, having atomic number 29 and electronic configuration 2.8.18.1. Loss of the outermost electron gives the cuprous ion Cu, and a second electron may be lost in the formation of the cupric ion Cu. ... 

The reason usually cited for the great similarity in the properties of the lanthanides is that they have similar electronic configurations in the outermost 6s and 5d orbitals. This occurs because, at this point in the periodic table, the added electrons begin to enter 4f orbitals which are fairly deep inside the atom. These orbitals are screened quite well from the outside by outer electrons, so changing the number of 4/electrons has almost no effect on the chemical properties of the atom. The added electrons do not become valence electrons in a chemical sense—neither are they readily shared nor are they readily removed. 

The noble gases, located at the end of each period, have electron configurations of the type ns2np6, where n represents the number of the outermost shell. Also, n is the number of the period in the periodic table in which the element is found. 

The configuration of electrons around the nuclei of atoms is related to the structure of the periodic table. Chemical properties of elements are mainly determined by the arrangement of electrons in the outermost valence shells of atoms. (Other factors also influence chemical... 

The physical and chemical properties of an atom are determined by the number and configuration of electrons in its electronic retinue. These are arranged in layers or shells, in a well-defined order. Some atoms have more shells than others, or indeed their shells are more complete and better organised. Chemical properties and molecule formation are determined by the outer shell. This is because only the outer electrons can mediate in chemical bonds, playing the role of a common currency. Atoms in the first column of Mendeleyev s periodic table have a single electron in their outermost shell, whilst those in the second column have two, and so on, until we reach the noble gases which have eight electrons in their outer layer (except for helium, which has two). 

In summary, it appears that the chemical activity of the elements is based primarily on electron configuration and then on outermost electron distance from the nucleus. Mostly because of their electron configuration, the transition metals, in the middle of the periodic table (next to the noble gases), are the most stable elements. They are not very reactive with other elements. This is why these transition metals, the so-called heavy metals, make such good jewelry material. However, other important factors are their shiny luster, ductility, and malleability. 

The outermost electrons, often called the valence electrons, are primarily responsible for the chemical properties of the elements. It follows that the elements in a specific group will show similar characteristic oxidation numbers (charges, also called valences) and display a trend in characteristics. Even though electron configurations were not known when the earliest periodic tables were formulated, the elements were placed by similarity of characteristics. 

With lithium (Z = 3) there are the two electrons in a spherical cloud (as with helium) plus a third electron. In most cases, in considering the electronic configurations of the element, the last electron is the only one that need be considered, all the remaining having been present in the preceding atom in the periodic table (there are a few important exceptions, however). For the third lithium electron there are no more possible combinations of quantum numbers where w = 1 since neither l or m can exceed zero if n is only one. The last (outermost) electron of lithium has the quantum numbers ... 

The periodic table is a tremendous source of information for students who learn to use it well. In Chapter 4, we will learn to use the periodic table to predict the electronic configuration of each of the elements, and in Chapter 5, we will use it to predict outermost electron shell occupancy. The table s numeric data are used in later chapters on formula calculations and stoichiometry, and its information on chemical trends is applied in the chapters on bonding and molecular structure. 

Rare earth elements have similar configurations in the two outermost shells. They exhibit typical metallic properties in chemical reactions. They tend to lose three electrons and exhibit a 3+ valence state. From the Periodic Table of the elements, rare earth elements are classed as less reactive than alkali metals and alkaline earth metals but more reactive than other metals. They should be stored in an inert liquid otherwise they will be oxidized and lose their metal luster. The metal reactivity increases gradually from scandium to lanthanum and decreases gradually from lanthanum to lutetium. That is to say, lanthanum is the most reactive metal of the 17 rare earth elements. Rare earth metals can react with water and release hydrogen. They react more vigorously with acids but do not react with bases. 

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