Question

Write the electron dot structure for the following compounds:
(1) ${\text{H}}_{\text{2}}$ (2) ${\text{O}}_{\text{2}}$ (3) ${\text{N}}_{\text{2}}$ (4) $\text{C}{\text{O}}_{\text{2}}$ (5) ${\text{S}}_{\text{8}}$ (6) ${\text{H}}_{\text{2}}\text{O}$ (7) $\text{N}{\text{H}}_{\text{3}}$ (8) $\text{CC}{\text{l}}_{\text{4}}$ (9) $\text{C}{\text{H}}_4$ (10) ${\text{C}}_5{\text{H}}_{\text{12}}$ (11) ${\text{C}}_4{\text{H}}_8$ (12) ${\text{C}}_5{\text{H}}_8$ (13) ${\text{C}}_7{\text{H}}_{\text{12}}$ (14) ${\text{C}}_5{\text{H}}_{10}$ (15) $\text{Cyclopropane}$ (16) $\text{Cyclobutane}$ (17) $\text{Cyclopentane}$ (18) $\text{Cyclohexane}$ (19) $\text{Benzene}$

Answer 1

Hint: Dot structure of chemical compounds also known as Lewis structure or Lewis dot formula. Lewis first proposed the dot structure of molecules in which all the valence electrons (electrons present in the outermost shell) of an atom in a molecule is represented by dots. The number of dots around the atomic symbol denotes the total number of valence electrons; these electrons mainly take part in the chemical bonding of atom.
- A covalent bond is formed by the mutual sharing of electrons between the atoms to complete their octet.

Complete step by step answer:
(1) In the hydrogen molecule two hydrogen atoms are attached through a single bond by mutual sharing of one, one electron by each hydrogen atom. A single dot represents the single electron.                         
                                         

(2) In an oxygen molecule two oxygen atoms are attached through one double bond by sharing four electrons. They also have two lone pair (pair of electron) in their valence shell.
                               

  
(3) In nitrogen molecules two nitrogen atoms are attached through a triple bond, they complete their octet by sharing six electrons.
                                     

 (4) Carbon atoms have four electrons in the valence shell, it completes their octet by sharing four electrons with two oxygen atoms and forms two double bonds.
(5) The shape of ${\text{S}}_{\text{8}}$ molecule is crown shape. In this molecule each sulphur atom has six electrons in the valence shell. They are attached to each other by a single bond. Each sulphur atom is attached with two sulphur atoms and share four electrons. 
                                          

(6) In water molecules an oxygen atom attached with two hydrogen atoms by mutual sharing two electrons with each hydrogen atom.
                                           

(7) In $\text{N}{\text{H}}_{\text{3}}$ a nitrogen atom attached with three hydrogen atoms by mutual sharing of six electrons.
                                    

(8) In $\text{CC}{\text{l}}_{\text{4}}$, a carbon atom attached with four chlorine atom by sharing of eight electrons.
                                

(9) In $\text{C}{\text{H}}_4$, a carbon atom is attached with four hydrogen atom by sharing of eight electrons.
                                        

(10) In ${\text{C}}_5{\text{H}}_{\text{12}}$, carbon atoms attached in a chain by forming single bond with each other.
                                          

(11) In ${\text{C}}_4{\text{H}}_8$carbon atoms are attached with each other through single or double bonds.
                                         

(12) In ${\text{C}}_5{\text{H}}_8$ unsaturation factor is two, so carbon atoms attached with single or triple bond both.
                                         

(13) In ${\text{C}}_7{\text{H}}_{\text{12}}$ carbon atoms attached with each other with single bond (in cyclic structure) or through single bond or double bond in open chain.
                                  

(14) In ${\text{C}}_5{\text{H}}_{10}$ in this compound carbon atom attached with each other by forming single or double bonds.
                                     

(15) In Cyclopropane the three carbon atoms are attached with a single bond in a cyclic manner.
                                              

(16) In $\text{Cyclobutane}$ four carbon atoms are attached with single bond and forms a cyclic structure.
                                          

(17) In $\text{Cyclopentane}$ five carbon atoms attached with a single bond and forms a five member ring.
                               

(18) In $\text{Cyclohexane}$ six carbon atoms attached with a single bond and forms a five member ring.
                                   

(19) In $\text{Benzene}$ carbon atom attached with each other by forming single bond and double bond and forms a six member ring.
                              

Note: A shared pair of electrons in between two atoms contributes to the electronic configuration of both the sharing atoms. Lewis structure helps in the study of covalency and stability of a molecule.