Alkaline earth metals
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The elements in group 2 are known as the Alkaline Earth Metals. As you move down the group, an extra shell of electrons is added, increasing the atomic radius. This can also explain the observed trends in ionisation energy and melting point.
Alkaline Earth Metals, except radium, follow specific trends in reactivity. They all react with hydrogen gas to form metal hydrides. Similarly, they also react with halogens to form metal halides. With the exception of beryllium, they form metal oxides upon interaction with oxygen, and metal hydroxides when they react with water.
Alkaline Earth Metals have many uses in industrial processes. The reductive power of magnesium is essential for the extraction of titanium metal from its ore. Calcium, in its oxide and carbonate forms, is also needed to remove toxic gases from flue columns. The insolubility of barium sulphate makes it safe for use in medical imaging.
Alkaline Earth Metal hydroxides increase in solubility down the group, this is due to the corresponding decrease in lattice energy. A lower lattice energy means it's easier for the molecule to be split into its soluble metal and hydroxide components. However, the sulphates decrease in solubility down the group, due to their larger ionic size.
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