The compound MgCl 2 formation from its ions:

Mg2+ gets ‘Ne’ configuration and

Each Cl–gets ‘Ar’ configuration

Mg2+ (g) + 2Cl – (g) → MgCl 2 (s)

One ‘Mg’ atom transfers two electrons one each to two ‘Cl’ atoms and so formed Mg2+ and 2Cl – attract to form MgCl2 .

Eg-3. Formation of di sodium monoxide(Na2 O):

Di sodium monoxide formation can be explained as follows: Cation formation (Na+ formation):

2Na (g) → 2Na+ (g) + 2e-

Electronic configuration   2, 8, 1     2, 8
or    [Ne] 3s1   [Ne]

Anion formation (O2-, the oxide formation):

O (g) + 2e-→ O2-

Electronic configuration2, 6     2, 8
or   [Ne] 2s2 2p4 [He] 2s2 2p6 or [Ne]

The compound Na2 O formation from its ions is as shown.

2Na+ (g) + O2- (g)→ Na2 O(s)

Two ‘Na’ atoms transfer one electron each to one oxygen atom to form 2Na+ and O2-

Each Na+ gets ‘Ne’ configuration and O2- gets ‘Ne’ configuration.

These ions (2Na+ and O2-) attract to form Na2 O.

Eg-4. Formation of aluminium chloride (AlCl 3 ):

Aluminium chloride formation can be explained as follows: Formation of aluminium ion (Al3+), the cation:

Each aluminium atom loses three electrons and three chlorine atoms gain them, one electron each.


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