# Consider the Lewis structure below. What are the formal charges of each atom?

Apr 24, 2017

H = +1 (B)
O = -2 ( D)
C = +2 ( A)
N = -3 (G)

#### Explanation:

The Hydrogen loses one electron to the Oxygen which has a higher electron negativity
The Hydrogen loses one electron to the Carbon as well which also has a higher electron negativity.

The Oxygen gains one electron from the Hydrogen and one electron from the Carbon both of which have lower electron negativity.

$O = - 1 + - 1 = - 2$

The Carbon gains one electron from the Hydrogen (-1) and loses one electron to the Oxygen ( +1) and loses two electrons to the Nitrogen.

$C = - 1 + 1 + 2 = + 2$

Nitrogen gains two electrons from the Carbon ( -2) and one electron from the Hydrogen (-1)
$N = - 2 + - 1 = - 3$

The total molecule will have an approximate value of zero so the charges should add up to zero.

 3 xx H = 3 xx +1 = +3  1 xx O = 1 xx -2 = -2
 1 xx C = 1 xx +2 = +2  1 xx N = 1 xx -3 = -3

$+ 3 + - 2 + 2 + - 3 = 0$

May 18, 2017

The formal charge on every atom is zero.

#### Explanation:

Formal charge is the charge that an atom appears to have when its valence electrons are counted according to certain arbitrary rules:

• Lone pair electrons belong entirely to the atom.
• Half of the shared bonding electrons belong to the atom.

In symbols, you get the formula

color(blue)(bar(ul(|color(white)(a/a) FC = VE – LP – 1/2BEcolor(white)(a/a)|)))" "

where

$V E =$ the number of valence electrons in an isolated atom
$L P =$ the number of lone pair electrons
$B E =$ the number of bonding electrons

For $\text{H} , F C = 1 - 0 - \frac{2}{2} = 0$

For $\text{C} , F C = 4 - 0 - \frac{8}{2} = 0$

For $\text{N} , C F = 5 - 2 - \frac{6}{2} = 0$

For $\text{O} , F C = 6 - 4 - \frac{4}{2} = 0$