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Jasmin Argueta 1K
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Postby Jasmin Argueta 1K » 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

Posts: 62
Joined: Fri Sep 28, 2018 12:17 am

Re: Shortcut

Postby Sean_Rodriguez_1J » 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))

Jessica Dharmawan 1G
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Joined: Fri Sep 28, 2018 12:15 am

Re: Shortcut

Postby Jessica Dharmawan 1G » 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!

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Re: Shortcut

Postby DavidEcheverri3J » 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!

Saima Salam 3J
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Joined: Fri Sep 28, 2018 12:25 am

Re: Shortcut

Postby Saima Salam 3J » 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.

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