Page 1 of 1
Posted: Thu Nov 15, 2018 11:52 pm
What's the shortcut for formal charge? My PLF was teaching it but I was still a bit confused
Posted: Thu Nov 15, 2018 11:57 pm
The shortcut that you can use is Formal Charge = # of Valence Electrons - (# of Lone Pair Atoms + (1/2)(# of Bonding electrons))
Posted: Fri Nov 16, 2018 9:38 am
The shortcut is basically to first count how many electrons are surrounding a single atom. For example, when looking at the formal charge for Cl in PCl5, you would count that there are 6 lone electrons and then one electron right next to the Cl that is being shared with the P (in other words, only count each shared electron pair as one electron when using this shortcut). Therefore, there are 7 electrons surrounding the Cl. Then after, you would do # valence electrons - # electrons surrounding atom. The FC of Cl, then, is 7-7 = 0.
I hope I explained this clearly and that it helps!
Posted: Fri Nov 16, 2018 1:10 pm
for S/2, instead of counting how many electrons each bond has and dividing by two, you can just count how many lines (bonds) there are and not divide by anything. Just a quick tip to make your life easier. Ah-hah!
Posted: Fri Nov 16, 2018 10:50 pm
Just do the number of things attached to the atom; lone pairs counts as two things and a bond counts as one thing. So do the number of things attached - valence electrons of the atom and that is the shortcut.