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1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

4. Molecular Compounds

Lewis Dot Structures: Ions (Simplified)

4. Molecular Compounds

Lewis Dot Structures: Ions (Simplified): Videos & Practice Problems

Video Lessons Practice Worksheet

Topic summary

In Lewis dot structures, cations have fewer valence electrons due to electron loss, while anions have more from electron gain. For the anion BCl₄^-, calculate total valence electrons: boron (1) + chlorine (4 x 7) + 1 (for the charge) = 32. Place boron at the center, bond it to four chlorines, and ensure each chlorine follows the octet rule. Finally, enclose the structure in brackets with the charge in the top right corner. Understanding these principles is essential for accurately representing ionic compounds.

Lewis Dot Structures of Ions involves losing or gaining valence electrons to draw the most likely structure.

Lewis Dot Structures of Ions

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Lewis Dot Structures: Ions (Simplified) Concept 1

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Lewis Dot Structures: Ions (Simplified) Concept 1 Video Summary

In understanding Lewis dot structures, it's essential to recognize the behavior of cations and anions regarding their valence electrons. Cations, which are positively charged ions, have fewer valence electrons due to the loss of electrons, while anions, negatively charged ions, have more valence electrons because they gain electrons. This foundational knowledge is crucial when constructing Lewis dot structures.

For example, to draw the Lewis dot structure for the anion BCl₄^-, we first need to calculate the total number of valence electrons. The number of valence electrons corresponds to the group number of the elements in the periodic table. Boron (B) is in group 3A, contributing 3 valence electrons, and chlorine (Cl) is in group 7A, contributing 7 valence electrons. Since there are four chlorine atoms, we calculate:

Valence electrons from B: 3
Valence electrons from Cl: 4 × 7 = 28
Total from B and Cl: 3 + 28 = 31
Adding one more electron due to the negative charge: 31 + 1 = 32 valence electrons.

Next, we place the least electronegative element, boron, at the center and connect it to the four chlorine atoms with single bonds. Following the bonding preferences, we ensure that each chlorine atom achieves an octet by adding electrons around them until they each have 8 electrons. It's important to remember that hydrogen follows the duet rule, desiring only 2 electrons, but in this case, we are only dealing with chlorine atoms.

After distributing the 32 electrons, we find that all are used up, with each chlorine atom surrounded by 8 electrons. Since there are no remaining electrons, we then enclose the entire structure in brackets to indicate that it is an ion, placing the charge in the top right corner. Thus, the final representation of the Lewis dot structure for BCl₄^- shows boron at the center with four chlorine atoms bonded to it, all enclosed in brackets with the negative charge indicated.

In summary, when constructing Lewis dot structures for ions, it is vital to account for the total number of valence electrons, correctly position the central atom, ensure surrounding atoms satisfy their electron requirements, and properly denote the ionic charge in the final structure.

Problem

Draw the Lewis Dot Structure for the following cation:NH₄⁺.

Problem

Determine the Lewis Dot Structure for the following ion:O₂^2–.

Problem

Determine the Lewis Dot Structure for the following ion:SCl₄²⁺.

Problem

Draw the Lewis Dot Structure for the following ion:PCl₄⁺.

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How do you draw the Lewis dot structure for anions?

To draw the Lewis dot structure for anions, follow these steps: First, determine the total number of valence electrons by adding the group numbers of each element and accounting for the charge (add electrons for negative charge). Place the least electronegative element in the center and connect all elements with single bonds. Add electrons to surrounding elements to satisfy the octet rule. Place any remaining electrons on the central atom. Finally, enclose the structure in brackets and indicate the charge in the top right corner.

What is the significance of the octet rule in Lewis dot structures?

The octet rule is significant in Lewis dot structures because it helps predict the arrangement of electrons around atoms. Atoms tend to form bonds to have eight electrons in their valence shell, achieving a stable electron configuration similar to noble gases. This rule guides the placement of electrons in bonds and lone pairs, ensuring that each atom (except hydrogen, which follows the duet rule) has a complete octet.

How do you determine the total number of valence electrons in a polyatomic ion?

To determine the total number of valence electrons in a polyatomic ion, sum the valence electrons of each atom based on their group number in the periodic table. For anions, add extra electrons equal to the negative charge. For cations, subtract electrons equal to the positive charge. For example, in BCl₄^-, boron (group 3) has 3 electrons, each chlorine (group 7) has 7 electrons, and the negative charge adds 1 electron, totaling 32 valence electrons.

Why do cations have fewer valence electrons in Lewis dot structures?

Cations have fewer valence electrons in Lewis dot structures because they lose electrons to achieve a positive charge. This loss of electrons results in fewer valence electrons around the central atom. For example, if a neutral atom loses one electron to form a cation with a +1 charge, it will have one less valence electron in its Lewis dot structure.

What is the process for placing the charge on a Lewis dot structure for ions?

After drawing the Lewis dot structure for an ion, enclose the entire structure in square brackets. Then, place the charge of the ion in the top right corner outside the brackets. For example, for the anion BCl₄^-, draw the structure, enclose it in brackets, and place the negative charge outside the brackets in the top right corner.