Alkaline earth metals beryllium

Group IIB and know that this means the group of elements zine. cadmium and mercury, whilst Group IIA refers to the alkaline earth metals beryllium, magnesium, calcium, barium and strontium. 

Group 2A—Alkaline earth metals Beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra) are also lustrous, silvery metals, but are less reactive than their neighbors in group 1A. Like the alkali metals, the alkaline earths are never found in nature in the pure state. 

The alkaline-earth metals beryllium, magnesium, calcium, strontium, barium, radium. 

The second column from the left contains the alkaline earth metals, beryllium, magnesium, calcium, strontium, barium, and radium (Be, Mg, Ca, Sr, Ba, and Ra, respectively). Magnesium and calcium are present everywhere and are needed by our salty bodies and the salty bodies of our fellow creatures. Calcium is vital to bones, teeth, seashells, and exoskeletons. Calcium plays a critical role in the operation of our muscles as well as communication between cells. Because strontium is in this family, radioactive strontium, a fission product of certain atomic reactions, can be absorbed by the body and used as it would use calcium. Radium, another radioactive element, is also found in this family. 

Group 2 of the periodic table contains the alkaline earth metals beryllium, magnesium, calcium, strontium, barium, and radium. These elements are similar to the alkali metals in that they are shiny, ductile, and malleable. The alkaline earth metals have two electrons in their outermost shell. Although they are not as reactive as the alkali metals, the alkaline earth metals are rarely found pure in nature. 

The alkaline earth metal beryllium exists naturally in compounds that almost always are... 

The elements in group 2 are the alkaline earth metals beryllium Be, magnesium Mg, calcium Ca, stronhum Sr, barium Ba and radium Ra. The last one, radium, is more interesting for its radioachve properties than for its similarity with the other alkaline earth elements. It will be described in Chapter 52 The Radioactive Elements. The others will be treated here and in Chapters 15 and 16. 

Electrons are not only charged, they also have a characteristic physicists call spin. Pairing two electrons by spin, which has two possible values, up or down, confers additional stability. Bei yllium (Be, atomic number 4) has two spin-paired electrons in its second shell that are easily given up in chemical reactions. Beryllium shares this characteristic with other elements in column two, the alkaline earth metals. These atoms also generally form ionic bonds. Boron... 

As a consequence of its closed-shell electron configuration, zinc has a negative electron affinity, that is, the removal of an electron from Zn is exothermic. The electronegativity of zinc (1.588 PU) is intermediate between those of the alkaline earth metals and the first row transition metals and remarkably similar to that of beryllium (1.57 PU). 

Some physical and chemical properties of the alkaline earth metals are shown in Table II. It can be seen that beryllium is significantly different from the elements below it in the periodic table in most respects. The fact that the density of beryllium is greater than that of magnesium is perhaps surprising, but can be understood by noting that magnesium is both a more massive and a larger atom. The density of beryllium is to be compared to that of iron (7.9 g cm-3), titanium (4.5 g cm-3), and aluminum (2.7 g cm-3). 

The fact that NHCs form stable compounds with beryllium, one of the hardest Lewis acids known and without p-electrons to back donate, shows the nu-cleophilicity of these ligands. Reaction of l,3-dimethylimidazolin-2-ylidene with polymeric BeCl2 results in the formation of the neutral 2 1 adduct 23 or the cationic 3 1 adduct 24. The first NHC-alkaline earth metal complex to be isolated was the 1 1 adduct 25 with MgEt2- Whereas l,3-dimesitylimidazolin-2-ylidene results in the formation of a dimeric compound, the application of sterically more demanding l,3-(l-adamantyl)imidazolin-2-ylidene gives a monomeric adduct. ... 

Because of its toxicity, the number of well-characterized beryllium compounds of all types is much lower than that of the other alkaline earth metals. The largest number of the pubhshed berylhum structures involve oxygen donor ligands, " and beryllium amides have been reviewed, at least in part, under the aegis of wider-ranging surveys - of group 2... 

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