Chemical Formula Writing Practice

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Date:

Chemical formulas and molecular structures

🧪 Part 1: Ionic Compound Formulas

Remember: In ionic compounds, positive and negative charges must balance to equal zero.

1. Write the correct chemical formula for sodium chloride (Na⁺ and Cl⁻):

Formula: _____________

2. Write the correct chemical formula for magnesium oxide (Mg²⁺ and O²⁻):

Formula: _____________

3. Write the correct chemical formula for aluminium chloride (Al³⁺ and Cl⁻):

Formula: _____________

4. What is the difference between subscripts and superscripts in chemical formulas?

Subscripts show charge, superscripts show number of atoms

Subscripts show number of atoms, superscripts show charge

Both show the same thing

Neither are important in formulas

⚗️ Part 2: Polyatomic Ion Compounds

Hint: Use brackets when you need more than one polyatomic ion. Common polyatomic ions: NO₃⁻ (nitrate), SO₄²⁻ (sulfate), NH₄⁺ (ammonium)

5. Write the formula for calcium nitrate (Ca²⁺ and NO₃⁻):

Formula: _____________

6. Write the formula for ammonium sulfate (NH₄⁺ and SO₄²⁻):

Formula: _____________

7. Which statement about polyatomic ions is correct?

They are single atoms with a charge

They are groups of atoms that act as one charged unit

They only exist in covalent compounds

They cannot form ionic compounds

🔬 Part 3: Challenge Problems & Real-Life Applications

8. Write the formula for aluminium sulfate (Al³⁺ and SO₄²⁻):

Formula: _____________

9. Table salt (sodium chloride) and baking soda (sodium hydrogen carbonate, NaHCO₃) are both ionic compounds. Explain why ionic compounds like these dissolve well in water:

10. Extension Challenge: Iron can form two different ions: Fe²⁺ and Fe³⁺. Write the formulas for both iron chloride compounds:

Iron(II) chloride: _____________

Iron(III) chloride: _____________

11. Compare ionic and covalent compound formulas. What is the main difference in how their formulas are written?

Chemical Formula Writing Practice

Chemical Formula Writing Practice

🧪 Part 1: Ionic Compound Formulas

⚗️ Part 2: Polyatomic Ion Compounds

🔬 Part 3: Challenge Problems & Real-Life Applications

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