Name ionic compounds, including polyatomic ions

Answer Key - Grade 10 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Calcium nitrate has 1 calcium atom and 2 nitrate ions of 4 atoms each. How many atoms are in one formula unit, Ari?

   9 atoms
2. 2.

   Aluminum sulfate has 2 aluminum atoms and 3 sulfate ions of 5 atoms each. How many atoms are in one formula unit, Bo?

   17 atoms

3. Read this first

   Common polyatomic ions (IUPAC names)

   name	formula	charge
   carbonate	CO₃²⁻	2−
   hydrogen carbonate	HCO₃⁻	1−
   nitrate	NO₃⁻	1−
   sulfate	SO₄²⁻	2−
   phosphate	PO₄³⁻	3−
   hydroxide	OH⁻	1−
   ammonium	NH₄⁺	1+

4. 3.

   Using the table, which ion is positive, Kira?

   • Phosphate
   • Ammonium
   • Hydroxide
5. 4.

   Using the table, how does hydrogen carbonate differ from carbonate, Luz?

   • It has two more oxygens than carbonate
   • It adds an H and has a 1− charge
   • It is positive
6. 5.

   What is the name of NaHCO₃, Milo?

   • Sodium carbide
   • Sodium hydride
   • Sodium hydrogen carbonate
7. 6.

   What is the name of CaCO₃, Noah?

   • Calcium carbide
   • Calcium carbonate
   • Calcium tricarbonide
8. 7.

   What is the name of Mg(OH)₂, Pia?

   • Magnesium hydroxide
   • Magnesium oxide
   • Magnesium dihydride
9. 8.

   Why is calcium nitrate written Ca(NO₃)₂ and not CaNO₃₂, Ren?

   • The 2 is calcium's charge
   • The 2 applies to the whole NO₃
   • Brackets just make it look neater
10. 9.

    Why does CaCO₃ have no brackets, Tala?

    • It has only one carbonate
    • Carbonate is too small for brackets
    • Calcium is too small
11. 10.

    How many sulfur atoms are in Al₂(SO₄)₃, Zee?

    • 3
    • 4
    • 1