Definition of alkaline earth in US English:

alkaline earth

(also alkaline earth metal)


  • Any of the elements beryllium, magnesium, calcium, strontium, barium, and radium, occupying Group IIA (2) of the periodic table. They are reactive, electropositive, divalent metals, and form basic oxides which react with water to form comparatively insoluble hydroxides.

    • ‘This suggests, says Scerri, that helium belongs on the far left of the chart with the alkaline earth metals, which also have two electrons in their outer shells.’
    • ‘The members of the alkaline earth metals include: beryllium, magnesium, calcium, strontium, barium and radium (Ra).’
    • ‘The lower pull-down menu lets you mark groups of elements, such as the halogens or the alkaline earth metals, on the plot.’
    • ‘Like those of the Group 1 metals, the oxides of the alkaline earths can be dissolved in water to form bases.’
    • ‘Family 2 on the periodic table is the alkaline earth metals with two valence electrons.’
    • ‘Four important chemical family names of elements still widely used are the alkali metals, the alkaline earths, the halogens, and the noble gases.’
    • ‘Barium is the fifth element in Group 2 of the periodic table, the alkaline earth elements.’
    • ‘There are limits to such effects, however, because high concentrations of alkaline earths and the transition metal ions cause rupture of hydrogen bounds, base unstacking, and ultimately decrease of thermal stability of DNA.’
    • ‘This may reflect the concentration of alkaline earth metals (Ca, Sr) in soil and groundwater as is typical in dry climates.’
    • ‘The members of this group are commonly described as the alkaline earth elements.’
    • ‘In the oxide state it reacts with the alkali, alkaline earth, and heavy base metals to form titanates, a few of which are being studied in conjunction with cheaper methods of production.’