What is the formal charge for C2H6? Please Help Me!!!

1 Answer
May 13, 2018

Why ZERO.....

Explanation:

Formal charge is a bit of a pain to assign...but formally you could go back to the Periodic Table, and assign it from first principles. You got a formula of #C_2H_6#...and NUCLEAR charges are #6xx1_H+2xx6_C=18*"protonic charges"#...if the molecule is neutral there should be #18*"electronic charges"#. Let's see if there are:

A single covalent bond represents 2 electrons....and these are shared between 2 atoms for porpoises of assignment...so all the hydrogen atoms have 1 electron from this bond...and so the hydrogens are ELECTRICALLY neutral. Each carbon atom also has 4 electrons from each covalent bond....i.e. from the #C-C# or #C-H# bond ... it ALSO has 2 inner core electrons...formally the #1s^(2)# set on ATOMIC carbon, and these ARE NOT conceived to be involved in bonding.

There result is that EACH carbon has 6 electrons....there are SIX nuclear charges, 6 positive charges...and thus each carbon are also ELECTRICALLY neutral. And so this species is NEUTRAL.

We could also go to an ionic species, sodium chloride...which we represent as #Na^+Cl^-#. Now ionic bonding results from the transfer of charge to form discrete positive and negative ions.

#Na(s) + 1/2Cl_2(g) rarr Na^+Cl^(-)#

Here we gots sodium metal, #Z=11#..this is oxidized to #Na^+#, with 10 electrons..agreed? But chlorine is FORMALLY reduced..

#1/2Cl_2(g) +e^(-)rarr Cl^(-)#

And so chlorine did have 17 electrons ... it now has 18...and do you agree with assignment of positive and negative charge?

And so now can you tell us WHERE, i.e. which atom, has the formal charge in #H_3O^+#, #NH_4^+#, #NH_2^-#, #RO^(-)#, #H_3C^(-)""^(+)MgCl#? Good luck.

Here's another example, and here, and here. This will keep you occupied....