Alkaline Earth Metals
Definition and meaning of Alkaline Earth Metals in chemistry.
Alkaline earth metals are a family of reactive elements in Group 2 of the periodic table. They hold exactly two valence electrons in their outermost electron shell. These elements commonly form basic compounds when they react with water or oxygen.
In more detail
This famous chemical family includes beryllium, magnesium, calcium, strontium, barium, and radium. These metals are much more reactive than standard transition metals like iron or copper. However, they are noticeably less reactive than the extreme alkali metals found in Group 1.
You will never find them sitting as pure metallic elements in the natural environment. Their high chemical reactivity forces them to instantly bond with other elements in nature. They readily give away their two outer electrons to form a +2 cation.
As you move down the column on the periodic table, the atoms get much larger. This larger size makes it easier for the atom to lose its outer electrons. Therefore, the metals at the bottom of the group react much faster than those at the top.
Students often confuse alkaline earth metals with rare earth elements located elsewhere on the table. In truth, alkaline earth compounds are incredibly common across the surface of our planet. Magnesium sulfate naturally appears in the popular muscle treatment known as Epsom salt. Calcium carbonate makes up the solid structure of everyday chalk, natural limestone, and seashells.
Key facts
| Group | Group 2 of the periodic table |
|---|---|
| Valence Electrons | 2 |
| Common Cation | +2 |
| Reactivity | Increases down the group |
| Field | Inorganic Chemistry |
Calcium is a classic alkaline earth metal with the atomic number 20. Calcium metal itself is a shiny, silvery substance that slowly reacts with room-temperature water. Biology relies heavily on calcium ions to build hard bones and strong teeth in animals. In the industrial world, workers use calcium chloride compounds as a powerful winter de-icer. This common salt effectively melts dangerous ice on frozen roads and pedestrian sidewalks.
Frequently asked questions
Why do chemists call these specific metals 'alkaline'?
They earned this name because their oxides react with water to form highly basic solutions. Chemists use the word alkaline to describe any solution with a pH above 7.
What is the main difference between alkaline earth metals and alkali metals?
Alkaline earth metals have two valence electrons and naturally form +2 cations. Alkali metals only have one valence electron, form +1 cations, and react much more violently.
Why do alkaline earth metals become more reactive as you move down the group?
The atoms get physically larger as you move down the periodic table column. The outer electrons sit further from the nucleus and require less energy to pull away.