Examples of Sigma and Pi Bonds in Organic Molecules

📚 Quick Study Guide

⚛️ Sigma ($\sigma$) bonds: These are the strongest covalent bonds and are formed by head-on overlapping of atomic orbitals. All single bonds are sigma bonds. ⚗️ Pi ($\pi$) bonds: These are weaker than sigma bonds and are formed by the sideways overlapping of p-orbitals. Pi bonds are present in double and triple bonds. 📝 Single bond: 1 $\sigma$ bond. 📈 Double bond: 1 $\sigma$ bond + 1 $\pi$ bond. 💡 Triple bond: 1 $\sigma$ bond + 2 $\pi$ bonds. 🔎 Rotation: Sigma bonds allow free rotation around the bond axis, while pi bonds restrict rotation due to their sideways overlap. 🌡️ Reactivity: Pi bonds are more reactive than sigma bonds because they are more exposed and have lower bond energy.

🧪 Practice Quiz

1. Which of the following bonds is the strongest?
1. A. Pi bond
2. B. Sigma bond
3. C. Ionic bond
4. D. Hydrogen bond
2. How many sigma and pi bonds are present in ethene ($CH_2=CH_2$)?
1. A. 5 sigma, 1 pi
2. B. 4 sigma, 2 pi
3. C. 6 sigma, 0 pi
4. D. 1 sigma, 5 pi
3. In ethyne ($HC≡CH$), how many pi bonds are present?
1. A. 0
2. B. 1
3. C. 2
4. D. 3
4. Which type of bond restricts rotation around the bond axis?
1. A. Sigma bond
2. B. Pi bond
3. C. Ionic bond
4. D. Hydrogen bond
5. Which of the following molecules contains only sigma bonds?
1. A. $C_2H_4$
2. B. $C_2H_2$
3. C. $CH_4$
4. D. $CO_2$
6. Which bond is more reactive?
1. A. Sigma bond
2. B. Pi bond
3. C. Both are equally reactive
4. D. Neither is reactive
7. How many sigma and pi bonds are in benzene ($C_6H_6$)?
1. A. 6 sigma, 6 pi
2. B. 12 sigma, 3 pi
3. C. 3 sigma, 12 pi
4. D. 15 sigma, 0 pi