Write Lewis dot symbol for atom of the following element: 

$\mathrm{N}$

Write Lewis dot symbol for atom of the following element: 

$\mathrm{Br}$

Write Lewis symbols for the following atom and ion: 

$\mathrm{S}\mathrm{}$ and ${\mathrm{S}}^{2-}$.

Write Lewis symbols for the following atom and ion: 

$\mathrm{Al}$ and ${\mathrm{Al}}^{3+}$

Write Lewis symbols for the following atom and ion:

$\mathrm{H}$ and ${\mathrm{H}}^{-}$

Draw the Lewis structure for the following molecule: 

${\mathrm{H}}_2\mathrm{S}$

Draw the Lewis structure for the following molecule: 

${\mathrm{SiCl}}_4$

Draw the Lewis structure for the following molecule: 

${\mathrm{BeF}}_2$

Draw the Lewis structure for the following ion: 

${\mathrm{CO}}_3^{2-}$