Question

Calculate total number of valence electrons in $C{H}_{3}C{H}_{2}Cl$ :

• A. 34
• B. 20
• C. 17
• D. 38

Answer 1

The correct option is B 20

The atomic number of carbon $=6$
Electronic configuration of Carbon is: $\left[He\right]2s^{2}2p^2$
Number of valence electrons: $4$
Similarly, the number of valence electrons in Hydrogen $\left(H\right)$ and Chlorine $\left(Cl\right)$ are 1 and 7 respectively.In $C{H}_{3}C{H}_{2}Cl$, we have 2 carbon atoms, 5 hydrogen atoms and one chlorine atom. Hence, total number of valence electrons in $C{H}_{3}C{H}_{2}Cl=4\times 2+1\times 5+7=20$