Question

Draw the electron dot structure of ethyne and also draw its structural formula?

Answer 1

Electron dot structure:

• Electron dot structures or Lewis dot formulas can only be drawn if the molecular formula of the compound is fully known.
• It can be defined as the nature of the bond and position of atoms of the molecule which are connected within the molecule.

Method for calculating electron dot structure:

We can determine the electron dot structure of any given compound by the following steps:

• First, the total number of valence electrons present in the molecule has to be calculated by adding the individual valencies of each atom, which can be given as: $\mathrm{V}.\mathrm{E}=\mathrm{B}.\mathrm{E}+(-\mathrm{ve}\mathrm{charge})-(+\mathrm{ve}\mathrm{charge})$

(where V.E represents the total number of valence electrons and B.E denotes the number of electrons present in the bond pairs.)

• The least electronegative atom among the given molecule will be chosen as the central atom of the molecule or ion.
• Now the electrons shall be assigned to the atoms in dot or cross representation to denote only the single bonding among the molecules.
• Now, the lone pairs of electrons will be assigned to each atom belonging to the molecule, which can satisfy their octet configuration.
• After assigning lone pairs to each atom, a double or triple bond should be drawn if necessary to satisfy the valence of the octet of each atom.
• Also, the lone pair can be converted into a bond pair in order to satisfy the octet rule for two atoms.

The structural formula of Ethyne:

• Ethyne is commonly known as Acetylene.
• Ethyne is the simplest two-carbon alkyne with the chemical formula is ${\mathrm{C}}_2{\mathrm{H}}_2$.
• The molecular formula for Ethyne can be given as :

The electron dot structure of Ethyne:

• The total number of valence electrons present in ${\mathrm{C}}_2{\mathrm{H}}_2\left(\mathrm{Ethyne}\right)$$=10.$
• Here the central atom is carbon, whereas Hydrogen is chosen as the side atom.
• Each carbon has 4 valence electrons, from which it will use 3 of the electrons from each carbon to make a triple bond between them.
• And the rest of the 1 electrons from each carbon will be used to make a total of 2 single bonds with 2 hydrogen single atoms.
• Hence, the electron dot structure of ${\mathrm{C}}_2{\mathrm{H}}_2$ can be shown as:

Hence, the electron dot structure of ethyne ${\mathrm{C}}_2{\mathrm{H}}_2$ has been drawn above.