Alkaline Earth Metals

The alkaline earth elements are metallic elements found in the second group of the periodic table. All alkaline earth elements have an oxidation number of +2, making them very reactive. Because of their reactivity, the alkaline metals are not found free in nature. Originally the term “alkaline earths” referred only to the oxides of calcium, strontium, and barium. The definition was later broadened to include the entire Group 2 family of elements. This group commonly loses the two s orbital electrons found in their outermost energy level. The remaining ion then has the desired complete octet of s and p orbital electrons in its outermost energy level.

One of the signature properties of this group of elements is that they become increasingly soluble with a decrease in temperature. This is usually true only for gases. Just imagine stirring sugar into a glass of tea. If you want to make really sweet tea, you need to add the sugar before adding the ice. Hot tea will dissolve more sugar in the same volume than cold tea. If the sugar were calcium, more calcium would dissolve into the liquid as you added the ice.

The Alkaline Earth Metals are:

  • Beryllium (Be)
  • Magnesium (Mg)
  • Calcium (Ca)
  • Strontium (Sr)
  • Barium (Ba)
  • Radium (Ra)

Beryllium (Be)

Name: Beryllium
Symbol: Be
Atomic Number: 4
Atomic Mass: 9.012182 amu
Melting Point: 1278.0 °C
Boiling Point: 2970.0 °C
Number of Protons/Electrons: 4
Number of Neutrons: 5
Classification: Alkaline Earth Metals
Crystal Structure: Hexagonal
Density @ 293 K: 1.8477 g/cm3
Color: gray

Magnesium (Mg)

Name: Magnesium
Symbol: Mg
Atomic Number: 12
Atomic Mass: 24.305 amu
Melting Point: 650.0 °C
Boiling Point: 1107.0 °C
Number of Protons/Electrons: 12
Number of Neutrons: 12
Classification: Alkaline Earth Metals
Crystal Structure: Hexagonal
Density @ 293 K: 1.738 g/cm3
Color: grayish

Calcium (Ca)

Name: Calcium
Symbol: Ca
Atomic Number: 20
Atomic Mass: 40.078 amu
Melting Point: 839.0 °C
Boiling Point: 1484.0 °C
Number of Protons/Electrons: 20
Number of Neutrons: 20
Classification: Alkaline Earth Metals
Crystal Structure: Cubic
Density @ 293 K: 1.55 g/cm3
Color: Silvery