chemistry-class-11-unit-04-chapter-02-chemical-bonding-molecular-structure-l-2-7-kl9aeyiomju

### <Success style="font-size:25px"> Chemical Bonding Molecular Structure L-2 </Success>
### <primary style="font-size:24px"> Resonance structures </primary>
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- $O_3$ 
 - Valence electron = 3 $\times$ 6 = 18$e^-$
 - Bonded electrons = 2$\times$ 2 = 4$e^-$
 - total electrons = 18 - 4 = 14$e^-$

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<footer style = "font-size: 18px"> $\rightarrow$ Chemical bonding and molecular structure $\rightarrow$ <span style = "color:blue"> Resonance structures </span> $\rightarrow$ Resonance structures $\rightarrow$ Resonance structures </footer>

### <Success style="font-size:25px"> Chemical Bonding Molecular Structure L-2 </Success>
### <primary style="font-size:24px"> Resonance structures </primary>
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- For $O_3$, $\quad$ O-O=128 pm.
 -  Typical $\quad$ O-O=148 pm.
 - Typical $\quad$ O=O =121 pm.

- $BF_4^{-}$
 - Tetrahedral

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<footer style = "font-size: 18px">Chemical bonding and molecular structure $\rightarrow$ Resonance structures $\rightarrow$ <span style = "color:blue"> Resonance structures </span> $\rightarrow$ Resonance structures $\rightarrow$ Formal charges </footer>

### <Success style="font-size:25px"> Chemical Bonding Molecular Structure L-2 </Success>
### <primary style="font-size:24px"> Formal charges </primary>
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- Formal charge $=$ Number of valence $e^-$ $-$ Number of $e^-$ in unshared pairs $-$ $\frac{\text{No. of $e^-$ in bonding pairs}}{2}$
- Examples
 - $NH_4^{+}$
 - For N , 5-0-4 = +1
 - $NO_3^{-1}$
 - For N , 5- 0-4 = +1
 - For O , 6-6-1 = -1
 - 6-4-2 = 0
 - (-1)+(-1)+0+(+1) = -1

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<footer style = "font-size: 18px">Resonance structures $\rightarrow$ Resonance structures $\rightarrow$ <span style = "color:blue"> Formal charges </span> $\rightarrow$ Formal charges $\rightarrow$ Formal charges </footer>

### <Success style="font-size:25px"> Chemical Bonding Molecular Structure L-2 </Success>
### <primary style="font-size:24px"> Formal charges </primary>
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- $N_2O$

- 2 $\times$ N + 0

- 2 $\times$ 5 + 6 = 16 valence $e^-$

- Which is the best structure is decided by formal charges

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<footer style = "font-size: 18px">Resonance structures $\rightarrow$ Formal charges $\rightarrow$ <span style = "color:blue"> Formal charges </span> $\rightarrow$ Formal charges $\rightarrow$ Formal charges </footer>

### <Success style="font-size:25px"> Chemical Bonding Molecular Structure L-2 </Success>
### <primary style="font-size:24px"> Formal charges </primary>
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- Hypervalent compounds
- $PF_5$
 - P = 5 + 5 $\times$ 7 = 40 valence $e^-$
 - F = 5 $\times$ 2 = 10 
 -   = 3 $\times$ 2 $\times$ 5 = 30
- $\mathrm{SF}_6$
 - S has 12 valence $e^-$

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<footer style = "font-size: 18px">Formal charges $\rightarrow$ Formal charges $\rightarrow$ <span style = "color:blue"> Formal charges </span> $\rightarrow$  $\rightarrow$ Thank you </footer>