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Atomic Structure

The Reaction between Sodium and Chlorine.

Chlorine has 7 electrons in its outer shell.
It is in group 7 of the periodic table.

When an atom of chlorine reacts it will gain one electron from
sodium. The outer shell of chlorine will then have 8 electrons
and be full. The chloride ion will have an extra electron
and therefore an extra negative charge (shown as a - sign).

What is an Ionic Bond?

The electrostatic force of attraction between
the oppositely charged ions is called an ionic bond.

The electrons are shown as dots and crosses
to show how they have moved during the reaction.
In reality all electrons are identical.

The balanced chemical equation for the above reaction is

sodium + chlorine     sodium chloride.
2Na_(s)  +    Cl_2(g)                 2NaCl_(s)

Sodium chloride is a crystalline ionic compound.
It forms a giant structure.

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