What do electron configurations have in common

The alkali metals and alkaline earth metals have one and two valence electrons electrons in the outer shell , respectively; because of this, they lose electrons to form bonds easily and so are very reactive. These elements comprise the s block of the periodic table. The p block, on the right, contains common non-metals, such as chlorine and helium. The noble gases, in the column on the right, almost never react, since they have eight valence electrons forming a stable outer shell.

The halogens, directly to the left of the noble gases, readily gain electrons and react with metals. The s and p blocks make up the main-group elements, also known as representative elements. The d block, which is the largest, consists of transition metals, such as copper, iron, and gold. The f block, on the bottom, contains rarer metals, including uranium.

Elements in the same group or family have the same configuration of valence electrons, so they behave in chemically similar ways.

In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals.

For example, the electron configuration of the neon atom Ne is 1s 2 2s 2 2p 6. Because the noble gases are composed of only single atoms, they are called monatomic. At room temperature and pressure, they are unreactive gases.

Because of their lack of reactivity, for many years they were called inert gases or rare gases. However, the first chemical compounds containing the noble gases were prepared in Although the noble gases are relatively minor constituents of the atmosphere, natural gas contains substantial amounts of helium. Because of its low reactivity, argon is often used as an unreactive inert atmosphere for welding and in light bulbs.

The red light emitted by neon in a gas discharge tube is used in neon lights. Certain elemental properties become apparent in a survey of the periodic table as a whole. A metal is a substance that is shiny, typically but not always silvery in color, and an excellent conductor of electricity and heat. Metals are also malleable they can be beaten into thin sheets and ductile they can be drawn into thin wires.

A nonmetal is typically dull and a poor conductor of electricity and heat. Solid nonmetals are also very brittle. The elements with properties intermediate between those of metals and nonmetals are called metalloids or semi-metals.

Elements adjacent to the bold line in the right-hand portion of the periodic table have semimetal properties. Based on its position in the periodic table, classify each element below as metal, a nonmetal, or a metalloid. Based on its location in the periodic table, do you expect indium to be a nonmetal, a metal, or a metalloid? Classify each element as metal, non metal, transition metal or inner transition metal. Learning Objectives Know the classification of the different elements.

Define valence electrons. Describe how the number of valence electrons are related the arrangement of the main group elements and its chemical behavior. Family Features: Outer Electron Configurations Valence Electrons The valence shell is the outermost shell of an atom in its uncombined state, which contains the electrons most likely to account for the nature of any reactions involving the atom and of the bonding interactions it has with other atoms. Valence Electrons and the Periodic Table. Family Groups As previously noted, the periodic table is arranged so that elements with similar chemical behaviors are in the same group.

Group 1: The Alkali Metals The alkali metals are lithium, sodium, potassium, rubidium, cesium, and francium. Group 2: The Alkaline Earth Metals The alkaline earth metals are beryllium, magnesium, calcium, strontium, barium, and radium. The periodic table is a tabular display of the chemical elements organized on the basis of their atomic numbers, electron configurations, and chemical properties. Elements are presented in increasing atomic number. Elements with the same number of valence electrons are kept together in groups, such as the halogens and the noble gases.

There are four distinct rectangular areas or blocks. The f-block is usually not included in the main table, but rather is floated below, as an inline f-block would often make the table impractically wide. Using periodic trends, the periodic table can help predict the properties of various elements and the relations between properties.

It therefore provides a useful framework for analyzing chemical behavior and is widely used in chemistry and other sciences. The electrons in the partially filled outermost shell or shells determine the chemical properties of the atom; it is called the valence shell.

When two different atoms are bonded covalently, the shared electrons are attracted to the more electronegative atom of the bond, resulting in a shift of electron density toward the more electronegative atom. Such a covalent bond is polar , and will have a dipole one end is positive and the other end negative.

The degree of polarity and the magnitude of the bond dipole will be proportional to the difference in electronegativity of the bonded atoms. Thus a O—H bond is more polar than a C—H bond, with the hydrogen atom of the former being more positive than the hydrogen bonded to carbon.

Likewise, C—Cl and C—Li bonds are both polar, but the carbon end is positive in the former and negative in the latter. Although there is a small electronegativity difference between carbon and hydrogen, the C—H bond is regarded as weakly polar at best, and hydrocarbons in general are considered to be non-polar compounds. The shift of electron density in a covalent bond toward the more electronegative atom or group can be observed in several ways.

For bonds to hydrogen, acidity is one criterion. If the bonding electron pair moves away from the hydrogen nucleus the proton will be more easily transfered to a base it will be more acidic.

A comparison of the acidities of methane, water and hydrofluoric acid is instructive. Methane is essentially non-acidic, since the C—H bond is nearly non-polar. As noted above, the O—H bond of water is polar, and it is at least 25 powers of ten more acidic than methane.

H—F is over 12 powers of ten more acidic than water as a consequence of the greater electronegativity difference in its atoms. Electronegativity differences may be transmitted through connecting covalent bonds by an inductive effect. Replacing one of the hydrogens of water by a more electronegative atom increases the acidity of the remaining O—H bond.

Thus hydrogen peroxide, HO—O— H , is ten thousand times more acidic than water, and hypochlorous acid, Cl—O— H is one hundred million times more acidic. This inductive transfer of polarity tapers off as the number of transmitting bonds increases, and the presence of more than one highly electronegative atom has a cumulative effect. Return to Table of Contents. Functional Groups. Functional groups are atoms or small groups of atoms two to four that exhibit a characteristic reactivity when treated with certain reagents.

A particular functional group will almost always display its characteristic chemical behavior when it is present in a compound. Because of their importance in understanding organic chemistry, functional groups have characteristic names that often carry over in the naming of individual compounds incorporating specific groups.

In the following table the atoms of each functional group are colored red and the characteristic IUPAC nomenclature suffix that denotes some but not all functional groups is also colored.

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The periodic table shown here is severely truncated.