Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

11. Bonding & Molecular Structure

Lewis Dot Structures: Exceptions

General Chemistry

11. Bonding & Molecular Structure

Lewis Dot Structures: Exceptions

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Multiple Choice

Metalloids can sometimes adopt the bonding preferences of similar nonmetals. Based on your knowledge of expanded octets, draw the Lewis Dot Structure for the following ion, SiF₆^2–.

Lewis Dot Structure for SiF6^2- showing silicon bonded to six fluorine atoms.

Lewis Dot Structure for SiF6^2- with emphasis on expanded octet around silicon.

Detailed Lewis Dot Structure for SiF6^2- illustrating bonding and lone pairs.

Alternative representation of Lewis Dot Structure for SiF6^2- with fluorine atoms.

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Verified step by step guidance

Identify the central atom in the ion, which is silicon (Si) in this case.

Determine the total number of valence electrons available. Silicon has 4 valence electrons, and each fluorine atom has 7 valence electrons. Since there are 6 fluorine atoms, the total from fluorine is 6 * 7 = 42. Additionally, the 2- charge indicates 2 extra electrons, making the total 4 + 42 + 2 = 48 valence electrons.

Place the silicon atom in the center and arrange the six fluorine atoms around it. Connect each fluorine atom to the silicon atom with a single bond. Each bond uses 2 electrons, so 6 bonds use 12 electrons, leaving 36 electrons.

Distribute the remaining electrons to satisfy the octet rule for each fluorine atom. Each fluorine needs 8 electrons (including the bonding pair), so place 6 electrons (3 lone pairs) around each fluorine. This uses up all 36 remaining electrons.

Verify the structure by checking that all atoms have a complete octet and that the total number of electrons used matches the number calculated initially. The silicon atom can have an expanded octet, which is satisfied in this structure.