Answer:
To draw or sketch a Lewis structure, formula or diagram, the chemical formula of the compound is essential. Without it you can not even know what are the atoms that make it up, in our case it is the one observed in the reaction shown:
[tex]BF_{3}[/tex] + [tex]:NH_{3}[/tex] ⇒ F3[tex]F_{3} BNH_{3}[/tex]
In the structure obtained (see the Lewis structure in the drawing) the black dots correspond to the electrons of the non-shared pairs. Because hydrogen has a single electron and a single orbital available to fill, it forms only a covalent bond represented by a long dash.
The same goes for boron and fluorine but in this case the fluorine has pairs of free electrons.
Explanation:
Lewis's structure is all that representation of covalent bonds within a molecule or an ion. In it, said bonds and electrons are represented by long dots or dashes, although most of the times the dots correspond to non-shared electrons and dashes to covalent bonds.
All existing compounds can be represented by Lewis structures, giving a first approximation of how the molecule or ions could be.
