Alkaline earth metals
The alkaline earth metals form group 2. Two ns² valence electrons, a stable +2 oxidation state. Less reactive than the alkalis but still very electropositive.
Beryllium, magnesium, calcium, strontium, barium and radium make up this family. Their chemistry is dominated by the +2 state; their oxides form basic hydroxides (lime water Ca(OH)₂, baryta Ba(OH)₂) when dissolved in water.
Calcium and magnesium are essential to biology (bones, chlorophyll) and very abundant in the Earth's crust. Barium and strontium have medical uses (digestive imaging, bone treatments); radium is radioactive and was used in the early days of radiotherapy.
In pure form, all of these metals burn in air with a very characteristic coloured flame, exploited in fireworks: red for Sr, green for Ba.