A Guide to the Alkaline Earth Metals
Explore the reactive, shiny metals of Group 2 on the periodic table.
What Are Alkaline Earth Metals?
The alkaline earth metals are the six chemical elements in Group 2 of the periodic table. They are Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). Like their neighbors, the alkali metals, they are highly reactive, though slightly less so.
These elements are shiny, silvery-white metals that are relatively soft and have low densities. Their name comes from their oxides, which form alkaline (basic) solutions in water and were known to early chemists as "earths."
Key Characteristic: Two Valence Electrons
The defining chemical property of an alkaline earth metal is its electron configuration. Each element in this group has two electrons in its outermost shell (valence shell).
- They readily lose these two electrons to form a stable cation with a +2 charge (e.g., Mg²⁺, Ca²⁺).
- Losing these two electrons allows the atom to achieve the stable electron configuration of a noble gas.
This tendency to lose two electrons makes them very reactive, second only to the alkali metals.
Location on the Periodic Table
The alkaline earth metals are found in the second column of the periodic table, Group 2.
Properties and Uses of Alkaline Earth Metals
These metals are harder and have higher melting points than the alkali metals.
| Element | Symbol | Key Use(s) |
|---|---|---|
| Beryllium | Be | Lightweight alloys for aerospace, X-ray windows, non-sparking tools. |
| Magnesium | Mg | Very lightweight alloys (cars, laptops), fireworks (bright white light), chlorophyll in plants. |
| Calcium | Ca | Essential for bones and teeth, cement and mortar (as calcium carbonate), dietary supplement. |
| Strontium | Sr | Red color in fireworks and flares, specialized glass for CRT televisions. |
| Barium | Ba | Medical imaging (barium meals for X-rays), drilling fluids for oil and gas wells. |
| Radium | Ra | Radioactive. Formerly used in luminous paints (now replaced by safer materials). |
Key Takeaways
- Alkaline earth metals are in Group 2 of the periodic table.
- They are defined by having two valence electrons, which they lose to form a +2 ion.
- They are reactive metals, but generally less reactive than the alkali metals.
- These elements are harder, denser, and have higher melting points than alkali metals.
- They play crucial roles in biology (calcium, magnesium) and many industrial applications.