Alkaline Earth Metals Quiz

Alkaline Earth Metals and Their Compounds

• Alkaline earth metals are in Group IIA or 2 of the periodic table
• These include beryllium, magnesium, calcium, strontium, barium, and radium
• They're called alkaline earth metals because their oxides are basic (alkaline) and were found in the earth's crust (earths)
• Calcium, strontium, and barium oxides were known before the metals themselves
• The metals, when discovered, were also referred to as alkaline earths
• The elements are found in various minerals, with Be3Al2(SiO3)6 being an example for beryllium

Position in Periodic Table

• Group IIA elements are in the periodic table
• Examples include beryllium, magnesium, calcium, strontium, barium, and radium

Electronic Configuration

• Valence electron configuration is ns² (period n)
• Examples include Be (1s² 2s²), Mg (1s² 2s² 2p⁶ 3s²), Ca (1s² 2s² 2p⁶ 3s² 3p⁶ 4s²)
• The valence shell is ns²
• The penultimate shell has 8 electrons, except for beryllium (2 electrons in its outer shell)
• Beryllium has an abnormal electronic configuration

Physical Properties

• All are silvery-white metals
• They are soft, but harder than alkali metals due to stronger metallic bonding
• Hardness decreases as atomic number increases
• Atomic and ionic radii progressively increase down the group
• Density increases gradually from Be to Ca, then increases slightly up to Ra due to differences in crystal structures
• Melting and boiling points are higher than corresponding alkali metals
• First and second ionization energies decrease down the group
• Electropositive character increases progressively from Be to Ba
• Electronegativity is low and decreases as the atomic number increases
• Good conductors of heat and electricity due to presence of two loosely bound valence electrons
• Flame coloration depends on the element. E.g., calcium gives brick-red coloration, strontium crimson, barium green
• Reducing nature increases as the atomic number increases