Question

Represent each of the following molecules using Lewis notation:
(a) bromine gas $\left(B{r}_2\right)$ (b) calcium chloride $\left(CaC{l}_2\right)$ (c)carbon dioxide $\left(C{O}_2\right)$ (d) Which of the three molecules listed above contains a double bond?

Answer 1

Lewis Notation of :

a) Bromine gas :- $\left({Br}_2\right)$ Atomic number $=35$

Electronic configuration :-

${1S}^2{2S}^2{2P}^6{3S}^2{3P}^6{4S}^2{3d}^{10}{4P}^5$

Valence electronic configuration $={4S}^2{4P}^5$

Lewis Notation of Beryllium atom is $[:\ddot{Br}.]$

Two Bromine atoms combine to form $\left({Br}_2\right)$ gas

Bromine $\left({Br}_2\right)$ gas

b) Calcium chloride :- $CaC{l}_2$

$CaC{l}_2$ molecule has two chloride atoms and one calcium atom

atomic number of calcium is $20$ electronic configuration is

${1S}^2{2S}^2{2P}^6{3S}^2{3P}^6{4S}^2$

Valence electronic configuration is ${4S}^2$

Atomic number of chloride is $17$.

Electronic configuration is

${1S}^2{2S}^2{2P}^6{3S}^2{3P}^5$

Valence electronic configuration is ${3S}^2{3P}^5$

Lewis Notation of calcium is

$[\cdot Ca\cdot ]$ $Co$ less two electrons and becomes ${Ca}^{2+}$.

Lewis Notation of chloride is

$[\ast \ddot{Cl}\ast ]$ each chloride gains as election and becomes ${Cl}^{-}$.

C) Carbon dioxide : $\left({CO}_2\right)$

Carbon dioxide molecule consists of two oxygen atoms and one carbon atoms. Atomic number of carbon atom is $6$.

Electronic configuration is ${1S}^2{2S}^2{2P}^2$

Valence electronic configuration is ${2S}^2{3P}^2$

Lewis notation is $\left[\dot{\cdot C\cdot }\right]$

Atomic number of oxygen atom is $8$

electronic configuration is ${1S}^2{2S}^2{2P}^4$

Valence electronic configuration is ${2S}^2{2P}^4$.

Lewis notation is $\left[\ddot{:O\cdot }\right]$

Carbon dioxide will be formed as :-

d) Among the given molecules only ${CO}_2$ contains a double bond between a carbon atom and oxygen atom.