The alkaline earth metals or alkaline earths are a set of six elements found in the second group (column) of the periodic table. Atoms of each of these elements have two electrons in the outer electron shell. Take a look at the elements in this group and their common properties:
List of the Alkaline Earth Metals
There are six alkaline earths. In order of increasing atomic number, they are:
- Beryllium (Be)
- Magnesium (Mg)
- Calcium (Ca)
- Strontium (Sr)
- Radium (Ra)
- Element 120 will be an alkaline earth when it is discovered.
Alkaline Earth Metal Properties
Because each atom has two valence electrons, elements of this group share several common characteristics:
- Atoms have a full outer s electron shell (2 electrons), which means these elements form cations with a 2+ charge and have a 2+ oxidation state.
- Atoms have a low electron affinity and low electronegativity.
- All of the alkaline earths are shiny, silver-colored metals at ordinary temperatures and pressure.
- These metals are malleable and ductile.
- The alkaline earth metals tend to be soft, with relatively low densities, melting points, and boiling points for metals. The melting points and boiling points are still much higher than for nonmetals. While soft, these elements are harder than those of the alkali metal group.
- Elements of this group are moderately reactive, with reactivity increasing as you move down the periodic table (i.e., strontium is more reactive than calcium).
- The alkaline earth metals are found in compounds, not free in nature.
- The alkaline earths readily react with halogens (Cl, Br, etc.) to form halides. They also react with oxygen to form oxides.
- While not a property per se, it’s worth noting all of the alkaline earth elements are named for their oxides (the alkaline earths), which had the names beryllia, magnesia, lime, strontia, and baryta.