Question

Write a Lewis structure for each of the following molecules or ions. You may wish to review the chapter on chemical bonding.

$(a){\mathrm{H}}_3\mathrm{B}\mathrm{P}{\mathrm{H}}_3$

$(b){\mathrm{B}\mathrm{F}}_4^{-}$

$(c)\mathrm{B}\mathrm{B}{\mathrm{r}}_3$

$(d)\mathrm{B}{\left(\mathrm{C}{\mathrm{H}}_3\right)}_3$

$(e)\mathrm{B}(\mathrm{O}\mathrm{H}{)}_3$

Short answer

a.

b.

c.

d.

e.

Step-by-step solution

Lewis structure

The Lewis structures are the simple diagrams in chemistry that represents the atomic bonding and determines the presence or absence of lone pairs in a given molecule.

Valence electrons of elements

• The number of valence electrons in boron is 3.
• The number of valence electrons in phosphorus is 5.
• The number of valence electrons in fluorine is 7.
• The number of valence electrons in bromine is 7.
• The number of valence electrons in carbon is 4
• The number of valence electrons in oxygen is 6.
• The number of valence electrons in hydrogen is 1.

Determination of the Lewis structure

(a) Three hydrogens are linked to the boron atom and the other three hydrogen atoms are linked to the phosphorus atom. The structure of the given compound is as shown below.

Structure of compound (a)

(b) Four fluorine atoms are attached to the central boron atom and the compound has an overall negative charge of -1. The structure of the given compound is as shown below.

Structure of ion (b)

(c)Three bromine atoms are attached to the central boron atom. The structure of the given compound is as shown below.

Structure of compound (c)

(d)Three methyl groups are attached to the central boron atom. The structure of the given compound is as shown below.

Structure of compound (d)

(e) Three hydroxyl (-OH) groups are attached to the central boron atom. The structure of the given compound is as shown below.

Structure of compound (e)