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Reading the Bonds in a Phosphate Model 4 questions
Reading the Bonds in a Phosphate Model
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A display models a solid made from Ca2+ ions and PO43- ions. Inside each phosphate ion, phosphorus and oxygen atoms share electrons. The full solid has no net charge. A display card lists proposed counts of each kind of ion.
| Model | Ca2+ ions counted | PO43- ions counted |
|---|---|---|
| J | 2 | 2 |
| K | 3 | 2 |
| L | 3 | 1 |
Question 1
Which set of counts gives a total charge of zero?
- J only
- K only
- L only
- J and K
Question 2
Explain how the solid can contain both covalent bonds and ionic attractions. Identify the particles involved in each.
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A student writes the formula Ca3PO8 for the display card because the chosen count includes eight oxygen atoms. The card needs to preserve the count of intact phosphate ions.
Question 3
Write the formula that preserves both intact phosphate ions, and explain what the subscript outside the parentheses means.
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Question 4
In the counting model, what net charge remains if one calcium ion is removed from K and no other ion leaves? Explain.
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