Question

Write Lewis symbols for the following atoms and ions: $S$ and $S ^{2-}$ ; $Al$ and $Al ^{3+}$ ; $H$ and $H ^-$

Answer 1

(i) $S$ and $S ^{2-}$
The number of valence electrons in $sulphur$ is $6$.
The Lewis dot symbol of $sulphur$ $(S)$ is .
The dinegative charge infers that there will be two electrons more in addition to the six valence electrons.
Hence, the Lewis dot symbol of $S ^{2-}$ is .

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(ii) $Al$ and $Al ^{3+}$
The number of valence electrons in $aluminium$ is $3$.
The Lewis dot symbol of $aluminium$ $(Al)$ is .
The tripositive charge on a species infers that it has donated its three electrons.
Hence, the Lewis dot symbol is

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(iii) $H$ and $H ^-$
The number of valence electrons in $hydrogen$ is $1$.
The Lewis dot symbol of $hydrogen$ $(H)$ is
The uninegative charge infers that there will be one electron more in addition to the one valence electron.
Hence, the Lewis dot symbol is