Question

I am having a hard time doing the lewis structure for ClF3? If we do the calculation there should only be 2 bonds for Cl but that clearly is impossible as we have 3 fluorines?

Answer 1

To find the number of bonds it's number of electrons needed to complete the valence shell - number of valence electrons. I got (5)(8) - 32 = 4 so 4/2=2 bonds but for some reason my prof changed the 2 to a 3?

Answer 2

\[ClF _{3}\] has \[3(7)+1(7) = 28\] electrons to place around the atoms.
We know we need to place 6 electrons around each fluorine to get them 8 electrons and there are at least single bonds left over.
\[3(6) + 3(2) = 24\]
This leaves us with 4 electrons or 2 electron pairs. This is a trigonal bipyramidal for the electron shape with a t-shaped molecular shape.

So your drawing should have a line to each fluorine with 6 dots around each and 2 extra dots on the chlorine.

\[3(6) + 3(2) + 2(2) = 28\]