C. Construct the Lewis structure model for the ionic compound lithium iodide: 1. The electron configuration for the lithium ion is _ and the number of valence electrons in a lithium ion is . 2. The electron configuration for the iodide ion is and the number of valence electrons in an iodide ion is . 3. Write the Lewis symbols for each ion: Lithium ion: Iodide ion: 4. Write the Lewis structure for the ionic compound lithium iodide. D. Construct the Lewis structure model for the covalent compound hydrogen iodide. 1. The electron configuration for the hydrogen is and the number of valence electrons in hydrogen is . 2. The electron configuration for iodine is and the number of valence electrons in iodine is .
C. Construct the Lewis structure model for the ionic compound lithium iodide: 1. The electron configuration for the lithium ion is and the number of valence electrons in a lithium ion is . 2. The electron configuration for the iodide ion is and the number of valence electrons in an iodide ion is . 3. Write the Lewis symbols for each ion: Lithium ion: Iodide ion: 4. Write the Lewis structure for the ionic compound lithium iodide. D. Construct the Lewis structure model for the covalent compound hydrogen iodide. 1. The electron configuration for the hydrogen is and the number of valence electrons in hydrogen is . 2. The electron configuration for iodine is _ and the number of valence electrons in iodine is _
The Correct Answer and Explanation is :
1. Electron configuration of lithium ion (Li⁺):
Answer: 1s²
Explanation: Neutral lithium has an electron configuration of 1s² 2s¹. When lithium loses one electron to form Li⁺, it loses the 2s¹ electron, leaving it with 1s².
Number of valence electrons in Li⁺:
Answer: 0
Explanation: Li⁺ has a full 1s orbital (not in the outermost shell), but no valence electrons in the second shell. In ionic bonding, Li⁺ donates its single valence electron.
2. Electron configuration of iodide ion (I⁻):
Answer: [Kr] 5s² 4d¹⁰ 5p⁶
Explanation: Neutral iodine has 53 electrons. When it gains one electron to become I⁻, it gains a full octet in its outer shell (5p⁶), becoming isoelectronic with xenon.
Number of valence electrons in I⁻:
Answer: 8
Explanation: The extra electron completes iodine’s valence shell, giving it a full octet.
3. Lewis symbols:
- Lithium ion (Li⁺): Li⁺ (no dots since it lost its only valence electron)
- Iodide ion (I⁻): I⁻ surrounded by 8 dots (4 pairs) representing a full octet
4. Lewis structure of lithium iodide:
Answer:
Li⁺ :⁻I:
(8 dots around I⁻)
Explanation: Li⁺ donates its one valence electron to I⁻. The result is an electrostatic attraction between the positively charged lithium ion and the negatively charged iodide ion — a typical ionic bond.
D. Covalent Compound: Hydrogen Iodide (HI)
1. Electron configuration of hydrogen:
Answer: 1s¹
Explanation: Hydrogen has one electron in the 1s orbital.
Number of valence electrons in H:
Answer: 1
Explanation: Hydrogen has only one valence electron and needs one more to fill its shell (duet rule).
2. Electron configuration of iodine:
Answer: [Kr] 5s² 4d¹⁰ 5p⁵
Explanation: Iodine has 7 valence electrons, needing one more to complete its octet.
Number of valence electrons in I:
Answer: 7
Explanation: These are the electrons in the 5s and 5p orbitals.
Lewis structure for hydrogen iodide (HI):
Answer:
H—I with three lone pairs on I
(: represents lone pair electrons)
Explanation: H shares its 1 electron with I, forming a single covalent bond. Iodine completes its octet with 3 lone pairs (6 electrons) plus the shared pair. Hydrogen satisfies the duet rule.
Summary Explanation
The compound lithium iodide (LiI) is formed through ionic bonding, where lithium (Li) donates its single valence electron to iodine (I). Lithium becomes a positively charged ion (Li⁺), with the electron configuration of 1s², and zero valence electrons. Iodine gains that electron to become an iodide ion (I⁻), with a full octet (8 valence electrons), making its configuration isoelectronic with xenon. The Lewis structure shows Li⁺ with no dots and I⁻ surrounded by eight dots (four lone pairs), illustrating the electrostatic force holding the oppositely charged ions together.
In contrast, hydrogen iodide (HI) is a covalent compound. Hydrogen has one valence electron (1s¹) and needs one more to achieve a stable duet. Iodine has seven valence electrons and needs one more to complete its octet. In the covalent bond of HI, hydrogen and iodine share a pair of electrons, forming a single bond. This satisfies hydrogen’s duet and iodine’s octet. The Lewis structure shows H–I, with three lone pairs on iodine. This shared electron pair distinguishes covalent bonding from ionic bonding, which involves full transfer of electrons.
Overall, these two examples — LiI and HI — clearly illustrate the difference between ionic and covalent bonding. Ionic bonds form between metals and nonmetals through electron transfer, while covalent bonds form between nonmetals through electron sharing. Lewis structures help visualize electron arrangements and bonding types in both kinds of compounds.
