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The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). [1] The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.
Helium is an exception: despite having a 1s 2 configuration with two valence electrons, and thus having some similarities with the alkaline earth metals with their ns 2 valence configurations, its shell is completely full and hence it is chemically very inert and is usually placed in group 18 with the other noble gases.
As the group 2 elements (also referred to as the alkaline earth metals) contain two valence electrons, their chemistries have similarities group 12 organometallic compounds. Both readily assume a +2 oxidation states with higher and lower states being rare, and are less electronegative than carbon.
One characteristic that all do have in common is having three electrons in their valence shells. Boron, being a metalloid, is a thermal and electrical insulator at room temperature, but a good conductor of heat and electricity at high temperatures. [8] Unlike boron, the metals in the group are good conductors under normal conditions.
The s-block, with the s standing for "sharp" and azimuthal quantum number 0, is on the left side of the conventional periodic table and is composed of elements from the first two columns plus one element in the rightmost column, the nonmetals hydrogen and helium and the alkali metals (in group 1) and alkaline earth metals (group 2). Their ...
It is an alkaline earth metal, a relatively reactive group, although not nearly as reactive as the alkali metals. Like rubidium, it has 5 electron shells or energy levels, and in accordance with the Madelung rule it has two electrons in its 5s subshell. Strontium is a soft metal and is extremely reactive upon contact with water.
Since full saturation of the occupied valence orbitals to form a closed shell species requires a total of 20 electrons, the magic number 20 is fulfilled. The resulting complex has the formula: [M(CO) 8] q, where M is either a transition metal or alkaline earth metal and q is the charge of the ion. For all alkaline earth metals, q is -2.
This separation extends to other differences in physical and chemical behaviour between the light and heavier alkaline earth metals. [n 1] The post-transition metals are located on the periodic table between the transition metals to their left and the chemically weak nonmetallic metalloids or nonmetals to their right.