Duet Rule Examples: Understanding Stability for Small Atoms Like Lithium

📚 Quick Study Guide

• ⚛️ The duet rule states that atoms tend to gain, lose, or share electrons in order to achieve an electron configuration with two valence electrons. This is particularly relevant for small atoms like hydrogen, lithium, and beryllium.
• 🤝 Similar to the octet rule for larger atoms, the duet rule helps explain the stability of certain molecules and ions.
• 🥇 Lithium (Li), with an atomic number of 3, has an electron configuration of $1s^22s^1$. It tends to lose one electron to form $Li^+$, achieving a stable duet configuration of $1s^2$.
• ➕ The stability of $Li^+$ is due to its filled inner shell, mimicking the electron configuration of helium (He).
• 🧪 Understanding the duet rule is crucial for predicting the reactivity and bonding behavior of elements in the first and second periods.

Practice Quiz

1. Question 1: According to the duet rule, what is the ideal number of valence electrons for atoms like lithium to achieve stability?
   1. A) 6
   2. B) 8
   3. C) 2
   4. D) 10
2. Question 2: Which element is most closely associated with following the duet rule?
   1. A) Carbon
   2. B) Oxygen
   3. C) Lithium
   4. D) Sulfur
3. Question 3: What electron configuration does lithium (Li) achieve when it forms the $Li^+$ ion, adhering to the duet rule?
   1. A) $1s^22s^2$
   2. B) $1s^22s^1$
   3. C) $1s^2$
   4. D) $1s^1$
4. Question 4: Why is the $Li^+$ ion considered stable according to the duet rule?
   1. A) It has an incomplete inner shell.
   2. B) It has a filled outer shell with 8 electrons.
   3. C) It has a filled inner shell with 2 electrons.
   4. D) It has no electrons.
5. Question 5: Which noble gas does $Li^+$ isoelectronic with after following the duet rule?
   1. A) Neon
   2. B) Argon
   3. C) Helium
   4. D) Krypton
6. Question 6: What is the primary reason lithium tends to lose one electron?
   1. A) To achieve an octet configuration.
   2. B) To achieve a duet configuration.
   3. C) To become more reactive.
   4. D) To form covalent bonds.
7. Question 7: Which of the following statements accurately describes the duet rule?
   1. A) Atoms achieve stability with 8 valence electrons.
   2. B) Atoms achieve stability with 2 valence electrons, especially smaller atoms.
   3. C) Atoms always form covalent bonds.
   4. D) Atoms always form ionic bonds.