Drawing ions with dots and crosses

4 minAS Level3.7.1

AI-drafted, independently checked · not yet teacher-reviewed

By the end of this lesson

By the end, you can show electron transfer and the resulting charged ions in a dot-and-cross diagram.

Ions form by electron transfer

In an ionic dot-and-cross diagram, one atom's outer electrons transfer to another atom. Use dots for one element's electrons and crosses for the other's.

Draw the final ions in square brackets with their charges outside. The ionic attraction is between the oppositely charged ions; it is not a shared electron pair.

Worked example: Sodium chloride

Show what happens to the outer electron when sodium reacts with chlorine.

Have a go first?

The electron marks keep their original identity after transfer; brackets and charges show the ions.

One electron or two?

Multiple choiceQuestion 1 · Recall

In sodium chloride, what happens to sodium's one outer electron?

AIt transfers to chlorine.BIt is shared between sodium and chlorine.CIt disappears when sodium becomes an ion.DIt moves from chlorine to sodium.

Multiple choiceQuestion 2 · Apply

How many electrons transfer from magnesium to oxygen when MgO forms?

ATwoBOneCThreeDZero

Answer the 2 questions above to continue.

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