Group 2

Earth alkali metals

Shiny when freshly cut Tarnish upon exposure to O2 Soft (harder down group) Low density (increases down gp) Electrical conductors

Shiny when freshly cut Tarnish when exposed to o2 as reactive so forms thin oxide layer

Softness increases going down Weaker metallic bond due to increase in shielding

More shells so atomic radius increases going down More shielding experienced So easier to lose electron going down

Electrostatic attraction between positive metal ions and negative delocalised electron

Decreases down group Larger atomic size distance between positive metal ions and delocalised electrons increases Lower charge density Weaker metallic bonding

X(s) + 2H2O(l) -> X(OH)2(aq) +H2 (g)

X(s) + H2O(g) ~> XO(s) + H2

Reactivity Increases going down As atomic size increases So larger atomic radius Weaker metallic attraction between positive ion and delocalised electron

Little to no reaction

Vigorous heating or reaction w steam produces white solid (beryllium oxide) h2 gas bubbles

Slow reaction White ppt Colourless gas bubbles (h2)

Burns w white flame Produces white solid (MgO) H2 gas bubbles

Reacts vigorously Produces white solid that dissolves in water to form clear colourless limewater Ca(OH)2 H2 gas bubbles

Vigorous reaction Bright flame White solid CaO H2 bubbles

Prepare sample solution Add few drops of Barium Hydroxide Positive test = white ppt forms Because barium Sulfate is insoluble in water

Reagent: barium chloride Adding few drops of HCL Adding few drops of BaCl2 Positive test: white ppt of barium sulfate forms

Reacts vigorously

Reactions slowed stopping H bubbles from rising

Group 2 sulfate become sulfates become less soluble down group

Insoluble So used for x ray imaging to view digestive system to show outline of organs