Question

organic chemistry
loudon
roberts & company publishers
presented by macmillan learning
predict the approximate bond angles in the molecule.
h₂c=c=ch₂
h-c-h angle:
° c=c=c angle:
°

Explanation:

Step1: Analyze terminal C hybridization

Each terminal $\text{C}$ in $\text{H}_2\text{C=C=CH}_2$ has 3 electron domains (2 single bonds to $\text{H}$, 1 double bond to $\text{C}$), so it is $sp^2$-hybridized. For $sp^2$ hybridization, ideal bond angles are $120^\circ$.

Step2: Analyze central C hybridization

The central $\text{C}$ has 2 electron domains (2 double bonds to terminal $\text{C}$ atoms), so it is $sp$-hybridized. For $sp$ hybridization, ideal bond angles are $180^\circ$.

Answer:

H-C-H angle: $120$ °
C=C=C angle: $180$ °