Question

part 2 (1 point) rank these three species in order of increasing formal charge on the carbon atom. (note that ch3+ does not have a full octet.) question list (3 items) (drag and drop into the appropriate area) cn- co2 ch3+

Explanation:

Step1: Recall formal - charge formula

The formal - charge formula is $FC = V - N - \frac{B}{2}$, where $V$ is the number of valence electrons of the atom in isolation, $N$ is the number of non - bonding electrons, and $B$ is the number of bonding electrons. For carbon, $V = 4$.

Step2: Calculate formal charge of $CN^-$

In $CN^-$, carbon forms a triple bond with nitrogen and has one lone pair. So $N = 2$ and $B = 6$. Then $FC_{CN^-}=4 - 2-\frac{6}{2}=4 - 2 - 3=-1$.

Step3: Calculate formal charge of $CO_2$

In $CO_2$, carbon forms two double bonds with oxygen atoms and has no lone pairs. So $N = 0$ and $B = 8$. Then $FC_{CO_2}=4 - 0-\frac{8}{2}=4 - 4 = 0$.

Step4: Calculate formal charge of $CH_3^+$

In $CH_3^+$, carbon forms three single bonds with hydrogen atoms and has no lone pairs. So $N = 0$ and $B = 6$. Then $FC_{CH_3^+}=4 - 0-\frac{6}{2}=4 - 3 = + 1$.

Answer:

$CN^-