Many planets in our solar system contain organic chemicals including methane (ch4 ) and traces of ethylene (c2h4 ), ethane (c2h6 ), propyne (h3ccch), and diacetylene (hh). write the lewis structures for each of these molecules.

Explanation:

Methane (CH₄)

Valence electrons of carbon = 4

Valence electrons of hydrogen = 1  

The total number of the valence electrons  = 4 + 4(1) = 8

The Lewis structure is drawn in such a way that the octet of each atom and duet for the hydrogen in the molecule is complete. So,  

The Lewis structure is:

                H

                 :

     H    :    C   :    H

                 :

                H

Ethylene (C₂H₄)

Valence electrons of carbon = 4

Valence electrons of hydrogen = 1  

The total number of the valence electrons  = 2(4) + 4(1) = 12

The Lewis structure is drawn in such a way that the octet of each atom and duet for the hydrogen in the molecule is complete. So,  

     H         H

      :           :

     C  :   :   C  

      :            :

     H           H

Ethane (C₂H₆)

Valence electrons of carbon = 4

Valence electrons of hydrogen = 1  

The total number of the valence electrons  = 2(4) + 6(1) = 14

The Lewis structure is drawn in such a way that the octet of each atom and duet for the hydrogen in the molecule is complete. So,  

       H         H

         :           :

H    :  C    :   C  :   H

         :           :

        H          H

Propyne (H₃CCCH)

Valence electrons of carbon = 4

Valence electrons of hydrogen = 1  

The total number of the valence electrons  = 3(4) + 4(1) = 16

The Lewis structure is drawn in such a way that the octet of each atom and duet for the hydrogen in the molecule is complete. So,  

       H        

         :          

H    :  C    :   C  :   :   :   C   :  H

         :          

        H    

Diacetylene (HH)  

Valence electrons of carbon = 4

Valence electrons of hydrogen = 1  

The total number of the valence electrons  = 4(4) + 2(1) = 18

The Lewis structure is drawn in such a way that the octet of each atom and duet for the hydrogen in the molecule is complete. So,  

H    :  C   :   :   :  C   :   C  :   :   :   C   :  H

b. examine and describe cells

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.