Monday, 11 October 2010

Group S elements

… are group 1 and group 2 on the periodic table.

A level students should identify those as Alkali metals and alkali earth metals, despite their lack of “Metal-like” properties.

Group S are generally reactive, and are relatively soft for metals.

Group 1 elements are less dense than water.

Francium and Radium are radioactive, and Cesium will react very violently with water. (Explosion)

Group S compounds are more useful than the elements.

They’re naturally found as ores.

Mostly, all S elements are reactive with water making Alkali solutions.

e.g. Magnesium + Water >> Magnesium Hydroxide + Hydrogen

The lower down the table, the more reactive the elements, for example Barium is more reactive than Magnesium.

All reactions in group 2 are more violent than group 1.

Group 2 is soluble, but less soluble than Group 1.

Group 2 makes stronger alkali solutions  (11-14 on the pH scale)

The lower down the table, the stronger the alkality. This is useful for neutralising acidic soil, whilst the salt bi product gets trapped in clay.

Thermal Stability: Unreactive elements give reactive compounds. And the further down the S group, the more stable the element.

Hydroxides are more solube as we go down the S group.
+1 ions[Hydroxides] (Chlorides, Bromides, Iodides, Nitrates)

Carbonates are less solube as we go down the S group.
-2 ions [Carbonates] (Sulphates, Oxides)

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