In alkaline earth metals, atomic radius increases as we move down the group. Beryllium has small radius as compared with other alkaline earth metals.
The first ionization energy is the energy needed to remove the most loosely held electron from every single mole of gaseous atoms to make a single mole of gaseous ions. Note that the first energy of ionization decreases down the group. The ionization energy is governed by three factors:
Electronegativity is a measurement of an atom's tendency to attract an electrons bonding pair. It is typically measured on the Pauling scale, where a 4.0 electronegativity is assigned to the most electronegative element (fluorine). Just as the metal atoms grow larger, any bonding pair is gradually pulled away from the metal nucleus, thus becoming somewhat less attracted to the metal. In simple words, the elements are less electronegative down the group. The bonds between these elements and other elements such as chlorine are becoming more ionic when moving down the group. The bonding pair is ever more attracted to the more electronegative element from the Group 2 element.
Beryllium may be the first alkaline earth metal element and has the highest melting point of any element in the group. On Earth as well as in the universe, it is very rare and is not considered important for plant or animal life. It can be found only in compounds with other elements in nature. In solutions, only pH values below 5.5 remain in elemental form. Beryllium is extremely light with high ionizing energy and is mainly used to reinforce alloys.
It is the Earth's 8th most abundant element, 2 percent by mass. It is also the 11th most common element in the human body: fifty percent of magnesium ions are found in bones and for more than three hundred different enzymes, it is a necessary catalyst. Magnesium has a 923 K melting point and reacts very slowly with water at room temperature. It is also extremely flammable and once ignited it is extremely hard to extinguish. UV - protected goggles should be worn as a precaution when burning or lighting pure magnesium, as the bright white light produced can seriously damage the retina.
It is the fifteenth most important element on Earth and is usually found in the mineral celestite form. Strontium metal is slightly weaker than calcium and has a 1042 K melting point.
Radium is the alkaline earth metals' heaviest and most radioactive metal and it reacts explosively with water. Radium appears to be pure white, but it immediately oxidizes and becomes black when exposed to air. Since radium is a declining uranium product, it can be found in all uranium ores in trace amounts.
|Electron Configuration||Boiling Point||Flame Color||Atomic #||Mass (g)||Oxidation State(s)||Atomic Radius (pm)||Ionization Energy (kJ/mol)||Crystal Structure||Magnetic Order|
|Mg||[Ne]3s2||1363 K||Bright White||12||24.31||+1, +2||150||737.7||Hexagonal||Paramagnetic|
|Ca||[Ar]4s2||1757 K||Orange/ Red||20||40.08||2||180||589.8||Face Centered Cubic||Diamagnetic|
|Sr||[Kr]5s2||1655 K||Scarlet||38||87.62||2||200||549.5||Face Centered Cubic||Paramagnetic|
|Ba||[Xe]6s2||2170 K||Green||56||137.3||2||215||502.9||Body Centered Cubic||Paramagnetic|
|Ra||[Rn]7s2||2010 K||~||88||226||2||215||509.3||Body Centered Cubic||Non-magnetic|