Properties of Group 1, 2 and

halides

Group 1	Group 2	Group 13
LiCl water soluble solid Li+(aq) not acidic	BeCl2 water soluble solid Be2+(aq) weak acid	BCl3 gas reacts with water to give B(OH)3
NaCl water soluble solid Na+(aq) not acidic	MgCl2 water soluble solid Mg2+(aq) not acidic	AlCl3 water soluble sollid Al3+(aq) weak acid
KCl water soluble solid K+(aq) not acidic	CaCl2 water soluble solid Ca2+(aq) not acidic	GaCl3 water soluble solid Ga3+(aq) weak acid
RbCl water soluble solid Rb+(aq) not acidic	SrCl2 water soluble solid Sr2+(aq) not acidic	InCl3 water soluble solid In3+(aq) weak acid
CsCl water soluble solid Cs+(aq) not acidic	BaCl2 water soluble solid Ba2+(aq) not acidic	TlCl3 water soluble sol In3+(aq) not acidc

The table at the right summarises the acid-base properties of the chlorides of the Group 1, 2 and elements.  The three groups into which these can be divided is shown by the colours.  Note the similarity to the groups for the acid-base properties of the oxides/hydroxides.

Physical state and water solutions:
White group:
These compounds are ionic solids that dissolve in water to give hydrated ions.
Yellow group
The bonding in these compounds is predominantly ionic, and these dissolve in water to give hydrated ions.
Green group:
The B-Cl bond is covalent, and this compound exists as molecules.  This compound is a gas.  BCl₃ dissolves in water and reacts to form B(OH)₃ and HCl (a strong acid).

Acidity of cation hydrates:
Hydrated cations act as acids (proton-donors) when the attractive force between the metal ion and the oxygen of the associated water molecules is strong. 
 
Cation hydrates of ions having high charge density are weak acids.  Ions of high charge density are relatively small and highly charged.  These are shown in the yellow group.