What is the Difference Between Barium and Strontium?

Barium and strontium are both alkaline earth metals found in group 2 of the periodic table. They share some similarities, but there are key differences between the two elements:

1. Chemical Reactivity: Barium is more chemically reactive than strontium. Barium reacts quicker with water than strontium due to its lower first ionization energy. This is despite barium having a greater nuclear charge than strontium, which would normally decrease the reaction rate.
2. Softness: Barium is comparatively softer than strontium.
3. Atomic Radius: Barium has a larger atomic radius than strontium.
4. Ionic Radius: Barium and strontium have different ionic radii, which affects their geochemical behavior. Barium's ionic radius allows it to bind to potassium minerals, especially feldspars, while strontium is more easily absorbed by clayey minerals and organisms that form carbonate skeletons.
5. Concentration in Earth's Crust: Strontium is more abundant in the Earth's crust, with a concentration of 350-480 mg/kg, while barium has a concentration of 150-628 mg/kg.
6. Radioactivity: Strontium-90 is a radioactive isotope that is produced in nuclear explosions and can become incorporated into bone in people exposed to it. Barium does not have the same radioactive properties as strontium.
7. Leachability: Barium is more soluble in seawater than strontium due to its larger ionic radius.

Comparative Table: Barium vs Strontium

Here is a table comparing the differences between barium and strontium:

Barium and strontium are both alkaline earth metals found in group 2 of the periodic table. The key difference between them is that barium metal is more chemically reactive than strontium metal. Barium has a higher atomic number and atomic weight compared to strontium.